Hydroponics

http://www.peterdoyleconsultancy.com.au/crops.html#tomatos

Peter Doyle

Peter Doyle, is one of Australia's foremost hydroponics systems consultants and a passionate advocate for the merits of hydroponics. To Peter, hydroponics offers all the dynamics of certified organic produce grown in soil; and then some. Hydroponics uses exactly the same trace elements found in soil but without the soil; it is intensive farming, that is fungicide and pesticide free and it is grown without synthetic fertilisers. Additionally it is climate, weather & terrain independent and the methodology that Peter advocates recycles the nutrient solution and uses less water than alternative methods.

When Peter began commercially growing herbs and vegetables in the early nineties, he set about researching and developing techniques, methods and materials that inevitably found their way into the industry through the osmotic relationships he maintains with many leading suppliers. In 2002, and in answer to the needs of drought stricken Australian farmers, Peter developed a new hydroponic fodder growing system using a combination of expertise, experience, knowledge and a unique hydroponic feeding method. Designed to consistently produce high protein green feed in adverse conditions, the Commercial Hydroponic Fodder System (CHFS) utilizes environmentally sound WaterWise methods, and as such requires much less water than field grown crops. The design was granted a patent in 2003.

Now that hydroponically grown fodder is proven for commercial purposes the hydroponic systems Peter designs for plant cultivation are to be found spread across different parts of the globe from Morocco to the USA. Consequently many consider him as a leading figure in the industry worldwide and an Authority on hydroponic system design. More info is available on the ´Fodder´ link above.

The Consultancy

Aside from operating a commercially successful hydroponic herb growing business Peter advises government authorities and educational institutions; and designs customised Hydroponic System solutions and Livestock Fodder Systems for commercial enterprises, farmers, livestock & agricultural organisations.

Through his consultancy Peter and his team provide customers with either practical, straightforward information or they design and advise how to set up and run commercial hydroponic systems.

The response from PDC's clients indicates that what we do is meeting customers' expectations with consistent results being achieved in all areas of our market. We welcome and encourage customer communication about new ideas and improvements they have developed as these can only assist our Company and the industry to move forward in the direction it must surely go.

On this page you can find a brief overview of the most common crops grown in commercial hydroponic systems throughout Australia. It is by no means an exhaustive list of these crops, and we have included it only to serve as a reference point for prospective growers. If the crop you are thinking about growing is not listed, then please contact us, and we will try to fill in the gaps for you.

Tomatoes

One of the most popular crops grown in hydroponics today, tomatoes are a good option for hydroponic growers due to the demand for the fruit throughout Australia (and the world!). It must be noted however, that growing tomatoes is not for everyone due the relatively high labour input required between crops, and the need to pick quite large numbers on a regular basis. Care should therefore be taken before establishing a growing system based around this crop, and we would always recommend spending some time on an existing farm to get a feel for the amount of input required before committing to a commercial hydroponic tomato system.

There are currently a variety of different methods being used in the hydroponic production of tomatoes of which the most common are NFT and Drip Irrigation. NFT will provide the greatest yield at the least cost, but this has not been taken on by all growers yet for variety of different reasons (mostly related to the saying “If it’s not broke, don’t fix it”). But this is starting to change, and more and more growers are changing over to NFT.

A major consideration when thinking about setting up a hydroponic tomato farm is the initial cost involved. Because tomatoes are a vine crop and require support from above, you will need a hothouse that can support their weight. There are of course plenty of companies out there that can sell you one of these structures, but it is a major expense, and may place a strain on your budget. However, if you have a good market for tomatoes, this initial cost can be quickly recovered.

Tomatoes also require pollination to set their fruit, as well as a environmental management system to keep require as the plants like them for optimum growth. So be prepared for quite a sharp initial learning curve if you make the final decision to move into this field of commercial hydroponic farming, and always remember, you get out what you put in.

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Capsicum

Although capsicum and tomatoes are similar in their method of production, there are some significant differences. For a start, nearly all capsicum are currently grown in medium based systems as opposed to NFT. This system utilizes the “batch feeding” technique, which allows for climatic conditions to dictate the feeding frequency and volume, i.e when it is hot, you feed more at more regular intervals than when it is cold, to allow for increased uptake by the plants. It is by all accounts a tried and tested method of growing capsicum with many years of proven results, and should be carefully considered by all growers looking at starting a capsicum farm.

However, we are in some ways a “pro NFT” hydroponic consultancy, and would recommend that all new growers also have a good look at the nutrient film technique method before committing to any commercial growing system. We know that in a well designed NFT channel, results equal to drip feeding media based systems are easily obtainable, with a marked decrease in labor costs. Setup costs are much the same, with the only difference being how long the plant is left on the system. In a media based system plants will tend be grown as perennials and will produce many sets of fruits throughout the year, but

will require a fair amount of attention to ward of pests and long term nutrient imbalances. In NFT plants tend to be grown as annuals, and therefore only produce fruit for a limited period of time, but do not tend to suffer from many of the problems associated with the perennials due to the ability to remove any under productive or diseased plants after a much shorter period of time. With this type of crop, if the worst happens it is only a minor setback, and can usually be incorporated into a slightly revised planting schedule.

A couple of other points to note with capsicum are that as with other vine crops, capsicum require a hothouse or structure that can support the weight of the plant from above, and that you must always have a very good look at the local market to determine whether or not your business has the potential to be a success in its early stages before going ahead with your venture. With capsicum, you are very dependent on your market to make your business successful, with a relatively small margin for error

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Cucumbers

Cucumbers are in many respects similar to tomatoes and capsicum in their method of production, with the most notable difference being their vulnerability to cold temperatures. The air temperature in the hothouse cannot be allowed to dip below 70 deg F without stress occurring to the plant, and the nutrient solution will normally have to heated as well. This may increase energy costs significantly in colder regions, but could also be an advantage to prospective growers in hotter climates.

Again, as with tomatoes and capsicum, cucumbers can be grown as either a short term crop, or as a long term crop. Short term NFT crops offer a considerable saving on labour costs, and as such are being used more and more as the production method of choice for cucumbers. Other methods of cucumber include drip irrigation culture into mediums such as perlite and rockwool, and the Deep Flow Technique.

Hothouse structures must be capable of supporting vine crops weight, which coupled with the need to keep cucumbers over a certain temperature and the potential energy costs associated with this, mean that careful investigation of your market is essential before embarking on a cucumber growing venture.

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Herbs

The markets in Australia generally require two types of product, the first of which is the “fresh cut” product. This type of product can be grown in either NFT or medium based systems, as the leaves of the herbs are cut away from the roots for processing into sealed bags or containers.

The second type of product commonly seen on the Australian market today is “living plant” herbs. Here the plant is grown in NFT and harvested whole with the root system intact. The herbs are then placed into a plastic bag with a small amount of water or nutrient, and sold as a single unit. This method provides the retailer with a significant increase in shelf life thus reducing the wastage experienced with the fresh cut

herbs.

Commonly grown herbs in NFT are basil and coriander, and they seem to be particularly suited to this method of production. Herbs such as thyme, marjoram and sage are often grown in a medium based system, but can be grown just as well in NFT.

Most herbs can be grown in a variety of conditions and due to their relatively short lifespan, can be grown with a good degree of success in most climates. They also grow very well on the same system as lettuce, allowing a wider range of products to be marketed.

Growing herbs in NFT is one of the least physically demanding types of commercial hydroponic production, and within reason, can usually be operated by a husband and wife team.

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Lettuce

There are many different types of lettuce grown today which include all the different types of lettuce normally sold in supermarkets throughout Australia and NZ. The method of growing is nearly always NFT, which as with herbs, allows for the finished plants to be sold as either “fresh cut” or “living plant”.

While the market for lettuce in the bigger cities may be difficult to access, there are opportunities in regional areas for smaller systems of say 1,000 to 1,500 square meters to meet the demand for ‘local’ fresh produce. As with all commercial systems we can not over emphasize the importance of establishing a potential market first. Whether you develop a simple or ‘high tech’ commercial system, the exercise is pointless if you have nowhere to sell your produce.

Romain or cos lettuce are currently very popular amongst commercial hydroponic growers. Varieties include; Red Romaine (tolerant to both heat and cold), Paris White, Parris Island, Cos Verdi, Toledo, Marvel, Diamond Gem, and Little Gem to name a few.

Growing time for lettuce can be anywhere between 60 and 80 days, and these plants can often be grown outdoors with relative ease in hotter climates. This of course can save quite a lot money on the initial outlay for a commercial farm, and is one of the reasons that lettuce is so popular with many commercial hydroponic growers. Another reason is the ability to grow herbs such as basil and coriander alongside lettuce to increase the range of produce provided by the grower.

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Ornamentals

There are currently many different types of ornamental flowers under hydroponic production today, with some of the most common being gerberas, carnations, lisianthus, roses and chrysanthemums.

The main difference between ornamental crops and food crops (apart from the obvious), is the level of environmental control needed to achieve optimum growth. The parameters for ornamental production are

very rigid to say the least, and setup costs can be daunting.

Another problem being faced by hydroponic ornamental growers is competition from abroad in addition to the down turn in the tourism and hospitality industry. Careful consideration must be given prior to venturing into the commercial flower industry, where a confirmed market is essential. Also the threat of cheap ornamental imports from across the globe can mean that a once solid and reliable outlet for your produce can suddenly be faced with the option of reducing there costs considerably, and few retail sellers will be able to say no this sort of incentive. After all, if they don’t take the flowers at a cheaper price then the shop next door probably will, and they will lose business to them. With this in mind careful market research is an absolute must for this type of start up, and the worst case scenario must be your starting point.

Given the complexities in growing commercial ornamentals, a good alternative could be to ‘learn the ropes’ on a more forgiving hydroponic system such as herbs or lettuce, as there always tend to be a good market in most regions. As your knowledge and capability increase it may be possible to approach local ornamental retailers with some sample produce to see if they are interested. In this way you have something to show the retailer when you do your market research, in addition to having a good idea of your production costs (and therefore your break even price), and by then you should know whether or not ornamental growing is for you.

We don’t mean to sound negative on this subject, but it is no secret that at the moment current market conditions in Australia for ornamental plants are a bit volatile, and new start ups may experience significant difficulties in gaining a foothold into the market place. That said, if you have a good market, we will of course happily consult on ornamental flower production for you. Other crops include:-

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Other crops include :-

VINE CROPS

Tomatoes (Lycopersicon lycopersicum)Capsicum (Capsicum annum)Cucumber (Cucumis sativa)

HERBSDill (Anethum graveolens)Parsley (Petroselinum crispum)Chives (Allium schoenoprasum)Mint (Mentha app.)Tarragon (Artemisia dranunculus)Marjoram (Maiorana hortensis)Fennel (Foeniculum vulgare)Sorrel (Rumex acetosa)Chicory (Cichorium intybus)

LETTUCECrisphead (Lactuca sativa var. capitata)Butterhead (Lactuca sativa var. capitatis)Vietnamese (Lactuca sativa var. crispa)Romaine/Cos (Lactuca sativa var. longifolia)

ASIAN VEGGIESAmaranth (Amaranthus tricolour)

BRASSICAS

Broccoli (Brassica oleracea var. italica)Cauliflower (Brassica oleracea var. botrytis)Cabbage (Brassica oleracea var. capitata)Rocket (Brassica rapa . var. chinensis)Kale (Brassica oleracea var. acephala)

VEGETABLESAubergine (Solanum melongena var. esculentum)Carrots (Daucus carota)Spinach (Spinacia oleracea)Asparagus (Asparagus officinalis)Okra (Hibiscus esculentus)

ROOT VEGETABLESPotato (Solanum tuberosums)Radish (Raphanus sativus)Onion (Allium cepa)Carrot (Daucus carota)Spring Onion (Allium fistulosum)

SPICESRoot Ginger (Zingiber Officionale)

Buffalo Spinach (Enydra fluctuans)Chinese Flowering Cabbage (Brassica rapa var. parachinensis)Chinese Celery (Apium graveolens var. dulce)Hot Mint (Poligonum minus)Lemon Grass (Cymbopogon citratus)Lizard’s Tail (Hottuynia cordata)Mustard Green (Brassica juncea)Pak Choi (Brassica rapa var. chinensis)Pennywort (Centella asiatica)Perilla (Perilla frutescens)Thai Basil (Ocimum basilicum)Spearmint (Mentha viridis)Turmeric (Cucurma domestica)Water Convolvulus (Ipomea aquatica)Water Parsley (Oenanthe javanica)Watercress (Rorippa nasturtium-acquaticum)

Turmeric (Cucurma domestica)Curry Leaves (Murraya koenigii)

FRUITWatermelon (Citrullus lanatus)

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Our experience and expertise in the Hydroponics market is unrivalled in Europe…”

Let’s talk about Commercial Hydroponics…

With many years of experience HydroGarden is the UK leader in hydroponics. We have assisted many growers develop their businesses with our access to experts and consultants in a wide range of topics including plant biochemistry, analytical chemistry, commercial growers with crop specific knowledge, commercial installation experience and much more. Several directors within HydroGarden have owned and operated their own commercial hydroponic operations.

Hydroponics is also now recognised as an important research tool. It has particular advantages where various controls are needed such as the pharmaceutical industry and other areas of research where a clean root system is required for instance. In Australia hydroponics production has risen from 155 hectares in 1990 to 500 hectares in 1996. This growth continues.

In progressive, forward thinking countries throughout the world the commercial hydroponics industry has increased 4-5 fold during the last 10 years. It is currently estimated that the area under hydroponic cultivation is between 20,000 and 25,000 hectares with a farm gate value of US$6-8 billion.

HydroGarden believes that the future lies in locally grown and sold produce, limiting the ‘road miles’ applied to today’s food supplies. Whilst export opportunities will occur, the main development will be that smaller niche, locally based growers will sell to supermarkets, farmers markets and wholesale operations as well as the consumer direct. This method of growing our food is a more sustainable model than those currently practised. Today’s consumer has become increasingly aware of health and environmental issues, even water consumption and availability…these are all drivers for the further development of hydroponic growing techniques.

As a company HydroGarden can assist you to identify the most suitable system for your crop, location, skills and needs. We understand that different plants require different systems in different locations and as such can offer those systems how and when you need them…

Why use Hydroponics?

There are 5 forces threatening long term crop and food production in open field situations:

1 Increasing ultraviolet radiation2 Decreasing fresh water supplies and water quality3 Increasing top soil erosion and soil degradation4 Increasing resistance of insect pests and plant diseases to traditional chemical controls5 A convergence of natural cycles leading to extreme weather conditions

Further, open field production is hindered because the grower has no control over the growing environment. The result is that the grower cannot predict yields and is unable to budget effectively. The field grower cannot always ensure adequate aeration of the rootzone during periods of extended rainfall.

The results might be any of the following:

Anaerobic conditions will benefit the proliferation of fungus (Phytophthora sp.) and nematodes that will attack the roots and eventually kill the plant.

Roots need oxygen to respire and therefore are not productive when the soil is saturated for long periods.

Beneficial soil borne micro-organisms are eliminated, therefore exposing the roots to fungal and bacterial attack.

Rain and excessive irrigation on the soil will leach essential nutrients from the root profile. Nitrates can be washed through the soil profile and pollute streams, reservoirs and the sea.

Hydroponic nutrient solutions can be tailored to the plant requirements whereas in the field there is a tendency to over or under-fertilise. Nutrients in the soil are often fixed as insoluble compounds that are not available to plants and therefore a loss to the grower.

SOIL GROWNSmall plant - big root

HYDROPONICALLY GROWNBig plant - small root

Looking at the benefits

Irrigation water in field grown operations cannot be effectively recycled. Hydroponics can reduce irrigation water usage by 70% to 90% by recycling the run-off water. As water becomes scarce and

more important as a resource, the use of hydroponics and other water saving technologies will increase.

Fungal disease can be significantly reduced through controlled humidity. Hydroponic systems will reduce the amount of exposed moisture in the growing environment. Hydroponics will effectively prevent wetting the leaf surfaces which, in normal agriculture, provides the fungal spores with the perfect medium to proliferate.

All labour inputs associated with soil management, such as digging and weeding are substantially reduced with hydroponics.

The use of Integrated Pest Management (IPM) in protected environments is ideally suited to hydroponic growing techniques, especially when carried out in a protected environment such as a glasshouse or plastic/polythene tunnels. The use of IPM can virtually eliminate the need to use toxic and expensive chemical insecticides.

Taking all the above into account, it is easy to see why protected cropping in general and hydroponics especially is becoming increasingly important.

A hydroponically grown greenhouse plant:

Can be protected from increasing and damaging UV radiation

Offers the possibility of safe biological control of insect pests and diseases

Uses water that is reclaimed and reused

Allows nutrients to be reclaimed, re-balanced and re-used

Can be protected from unpredictable weather patterns

Has a good root system that is at reduced risk from contaminants and diseases

Makes very efficient use of labour, which is increasingly expensive in western economies

Can be grown to take full advantage of their genetic potential and produce outstanding crops by using optimum nutrient formulations

Can be producing at times when market prices are highest

Combine these factors with increasing public concern over food safety, pesticide residues and fungicide use; it is easy to see that the future of crop production favours hydroponic and greenhouse production. Especially when premium prices can be obtained and the demand is sustainable.

Global diversity…

Lettuce, strawberries and cut flowers are well known commercial hydroponic crops in Australia, and have been for the past decade and more. Tomatoes, pepper, cucumbers and cut flowers form the bulk of Dutch hydroponic crops. A number of UK growers have successful cucumber and tomato operations and many herb growers are moving into this form of cultivation. Nowadays plants for essential oils, rare herbs, medicinal plants and Chinese vegetables such as pak choi are more recent crops of great interest. There is a developing interest in growing plants for pharmaceutical and nutraceutical use. It is possible to grow practically any commercial crops hydroponically.

Commercial growers have been producing superbly flavoured hydroponic tomatoes for many years.

Speciality crops and even fruit trees can all be grown hydroponically. We have recently learnt of a commercial hydroponic potato business in the Southern Hemisphere !

We are seeing an increasing interest in the production of cut herbs and salad crops, driven by the demand for convenience foods that are also seen as ‘healthy’.The production of cut flowers is itself a huge market, the introduction of new more exotic plant types lends itself to hydroponic production as a means of growing the best quality from the outset and therefore making it more difficult for cheaper lower quality crops to compete.

We expect, in time, to see an increase in demand for edible flowers, especially for use in restaurants and hotel complexes.

Even fruit trees can be grown this way. In fact there are very few plants that cannot be grown hydroponically, the choice for a commercial operation is a pure economic one.

We produce a number of separate data sheets relating to various crop types and opportunities, this information includes some basic plant growing information as well as recommended or typical system types suitable for the crop. Whilst it is not exhaustive it will give the reader an idea of the potential for hydroponic crop production.

Commercial systems…

All commercial systems are active, in that some form of pump or feeding device is used to deliver fresh nutrient solution to the plants in an ongoing basis. These systems are more productive and are therefore the only type suitable for commercial production.

Of the active systems available they break down into either re-circulating or run to waste; run to waste systems are becoming less popular as environmental concerns and legislation restricts, or even prohibits, nutrient run off. However, if the run off can be managed to obtain a zero figure, these systems still have their place. As a company we encourage the use of re-circulating systems to maximise resource utilisation, but this is not always possible in certain circumstances. Re-circulating systems typically use one tenth of the water, a fraction of the minerals and takes up from one third to one tenth the space consumed in traditional agriculture.

There are a number of differing active systems available, but again these can be easily categorised into:

Nutrient Film Technique (NFT)Ebb & Flow (also referred to as Flood & Drain)Drip Fed Media Based CultureAeroponicsRaft Type Systems

Nutrient Film Technique (NFT)

Nutrient Film Technique (NFT) is both simple to understand, operate and maintain. Plants are grown in equally spaced holes in plastic gullys or formed plastic sheeting. A liquid nutrient solution of minerals and highly oxygenated water is pumped into the higher end of the gully, gravity draws the nutrient past the plant roots and then back to the nutrient tank, where the process is repeated.

As the nutrient solution flows past the plants the roots are bathed in a thin nutrient rich film of solution that is ideally balanced in terms of nutrition, oxygen, pH and strength. As this is an enclosed re-circulating active system it ensures maximum production combined with resource conservation.

The absence of growing media in NFT systems reduces costs but ensures the need to use high quality pumps and calls for a reliable power supply to those pumps. The plants will quickly wither and die if the system is left ‘dry’ during the heat of the day.

Drip Fed Media Based Culture

Often called ‘slab culture’, this is most popular form of commercial hydroponics in countries such as Holland. The plants are grown in a medium, most often Rockwool but more recently in CoCo Coir. However, sawdust and sand have been used in some instances!

Slab Culture tends to be used for longer-term crops such as tomatoes, cucumbers and peppers where a larger root system develops. The advantage of slab culture is that only intermittent feeding of the plants is required. Also, the media itself tends to hold a large amount of nutrients that are then available to the plants as needed. Often run off is limited to a small percentage to ensure adequate feeding, but excessive run off is both expensive and environmentally undesirable. As in ‘Ebb & Flow’, the media can act as a buffer in case of pump or electricity failure.Ebb & FlowEbb & Flow (or Flood & Drain) is a system where a tray or bed of plants are alternatively flooded and then drained with the required nutrient solution. The flooding of the media or plants acts to purge the media of stale oxygen depleted air and then draws in fresh oxygen rich air to the root-zone when the system drains back into the nutrient tank.

This system is more suitable for longer-term crops such as trees & cut flowers where larger root masses are likely. Ebb & Flow systems always use some kind of media that can act as a buffer in case of pumps or electricity failure. Also, because the system is less active than an NFT system the management of the nutrient solution is often less onerous than that of NFT.

Aeroponics

Aeroponics is a system where often no media is present at all and the roots of the plants are misted with the nutrient solution in a chamber or other suitable space. The mist has to be of a certain size (5 micron max) to maximise growth and the delivery of the mist is a problem in its own right. Blockages can occur and high-pressure pumps are often needed, this makes Aeroponics less suitable for commercial production. However, we are aware of Aeroponic systems being used for research and in some ‘niche’ applications.

The lack of any media in Aeroponics and the subsequent lack of buffering can be problematic, but Aeroponic is a fantastic system when clean, fresh roots are needed!

Raft Type Systems

Raft Type Systems are those where the plant being cultivated is ‘floated’ on top of the nutrient tank. The roots dangle in the nutrient and take up feed as needed. A large amount of water is generally needed for such systems and the need to oxygenate the solution is paramount. It would be easy to ‘drown’ the plants if the oxygenation system failed. Raft systems are generally regarded as a bit outdated, but do have their place in certain circumstances.

They are often cheap to construct and can be run without the use of nutrient pumps as long as oxygen is supplied to the system in suitable quantities.

Some concerns exist over the use of re-circulating systems and the potential danger of spreading disease throughout the system if it manifests itself. However, in our experience this danger can be greatly reduced and even eliminated through the use of nutrient sterilisation, strict cleanliness regimes or beneficial bacteria being used.

All of the system types discussed usually utilise automatic dosing controllers to constantly monitor and maintain the optimum nutrient strength and pH balance.

As a company, we can advise on all system types and the suitability of that system to an individual case.Whatever system is most suitable for your operation, we can supply it.

For any new grower we are happy to provide a small trial system at a special price. The cost of this system would be credited to the grower should a full size system be purchased as a result of the trial.

Getting started…

It is most important when considering the possibility of growing hydroponically, whether on a small or large scale, that you seek advice from a number of sources. Talk to potential customers and fully research the business. We will assist where ever possible. Carry out research before you start and plan to start small! Each market, each crop and every growing situation is different. It will be necessary to gain an overall understanding of the business and crop before any significant system expansion takes place.

Don’t rely on a single source when obtaining information on crop yields for a specific crop, check local as well as national and government sources.

We recommend the grower starts off with a small trial system, we can advise and assist with these too. A trial system enables the grower to get the hang of the basics of hydroponics. It is easy, but you have to learn how to use it properly, how to get the correct balance of nutrients for the correct flavour or colour and growth of the plant and how to recognise problems as they arise.

Buy a good book. We sell several that are crop specific, and do some reading. If possible visit an existing commercial grower - we may be able to help in providing contacts.

Ensure you perform adequate market research. Marketing is customer not product focussed. If possible innovate to continuously improve product benefits. Try to add value as this will attract new customers for your produce and ensure you keep existing ones.

There is much more to running a successful commercial operation than just growing high quality produce. HydroGarden can advise on various ways to market your produce and how to add value and with more general marketing advice.Growing hydroponically will give you the ability to time harvests to match restricted availability for certain crops, this aids in obtaining premium prices for the crop. If necessary, we have the expertise in other business topics such as finance, which may also assist.

By reading this brochure and by using the services offered, you will save time, effort and money.

All under one roof…

Please refer to our Commercial Price List for the complete range of our products.

Not only can we provide the system, lighting and nutritional requirements for your system, we also stock a large range of other essential items such as:

growing mediapropagating products

low and high pressure pipe fittingsnutrient pumpsgrowth promoting and flowering additivespH testing, adjustment and calibration productsnutrient testing and calibration productsnutrient sterilisation productsaeration productsmonitoring and dosing equipmentfilters and filtration productsplant support accessories to aid optimum growthbooks

and more....

It is important to remember that all components used in a hydroponic system must be non-toxic and must not react when exposed to the nutrient solution. This generally means plastic or stainless steel materials.

Trial Systems

As a company we would always recommend that a new grower purchase a trial system in the first instance. This will get you used to the techniques behind hydroponic cultivation and get used to the control of the nutrient strength and pH. HydroGarden Trial System Offer!

We are always happy to deduct the cost of this initial trial system from the cost of any full size system should you choose to purchase one. It all helps.

A helping hand

At Hydrogarden, we realise that a relationship starts, not ends, with a purchase of a system. We are able to assist from the business or system planning stage, all the way through to on-going grower support. We may even be able to help you buy or sell your business.

HydroGarden can assist you prior to starting growing with:

Water AnalysisCrop Specific NutrientsLocation Specific NutrientsLocation and Natural Environmental ConsiderationsCrop Considerations as well as Yield Forecasts and PredictionsSystem Layout, Specification and ConsiderationsEnvironmental Control and Protective Structural ConsiderationsProduction Factors and Operating CostsManagement and Grower ConsiderationsAdditional Resources that may be requiredSupplementary Lighting Layout (if necessary)Equipment Supply Business PlanningMarketing Advice

Once the system is operational, we can advise, or obtain advice on:

Crop Specific Problems or IssuesPlant Tissue AnalysisNutrient Analysis/Monitoring/Tissue Analysis and Nutrient Adjustment and Replenishment Equipment Supply or UpgradesLatest Technical Information and Innovations Equipment SupplyMarketing Advice

Embracing the new…

Energy Conservation and Renewable Energy

We firmly support all initiatives to reduce unnecessary energy consumption in the projects we are involved with. Where possible we will assist in lowering a grower’s dependence upon fossil fuels.

The use of energy efficient glass or plastic structures, energy curtains, heat sinks, correct design, location and layout, the correct use of ventilation and other initiatives can all assist in making the project successful and sustainable.

The use of bio-fuels and other alternative sources of power such as micro-turbines can all assist in making the commercial hydroponics industry a viable, long term one.

New Markets and Evolving Opportunities

Medicinal – Nutraceuticals – Cosmeceuticals – Pharmaceuticals – Essential Oils – Herbal Medicines - Healthy Food – Safe Food – Farmers Markets – Localised Supply - Hydro-0rganics - Utilisation of brown field sites - Urban Horticulture

Recent reports give reliable predictions that natural based products will penetrate the synthetic pharmaceutical markets by up to 30% over the next 3 years (from 2003). Where will these plant-based products be sourced? Nutraceuticals (foods that are beneficial to our health) are also expected to maintain the growth seen over the past decade. A number of these foods require plant-derived materials that are often found in a plant’s root zone. The use of hydroponic growing methods alone can ensure the clean, controlled product that is required. Pharmaceutical companies also need raw materials that are pesticide free, of high quality and have been grown in a controlled method…sound familiar? They have to be grown in controlled, clean environments such as hydroponics can provide. It is unlikely that this growth in demand will be met by ravaging the already delicate eco-systems represented by rainforests and similar natural resources.

In the USA it is common for high value foods to be grown hydro-organically, that is using organic nutrients in a hydroponic system.

The demand for more natural based products is unlikely to diminish in the foreseeable future. Combine these factors with the increasing interest in pesticide free, healthy, vitamin rich foods and you can see why we are so excited about the future prospects of our industry…

In conclusion…

Over the past 9 years, HydroGarden has been actively involved in the global Hydroponics industry and has gained a reputation for the supply of quality products at affordable prices. Our experience and expertise in the Hydroponics market is unrivalled in Europe and we know that commercial hydroponic systems are serious business. We have contacts with hydroponic companies and commercial growers worldwide.

So if we do not know the answer we can find someone who does!

As well as designing, supplying and maintaining systems, HydroGarden staff and directors have hands on experience of growing. This personal experience is something that few, if any other, firms can claim. We know what it is like when the insects attack or the varieties are wrong. We have also felt the joy of growing the best quality crops in the shortest possible time!

If you are considering entering into hydroponics on a commercial basis, we invite you to talk to us. Not only will you find our company friendly and efficient, our range of quality products and backup is the best available anywhere.

HydroGarden will talk with you about the system you need, the returns you will require and the obstacles you may encounter.

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Wikipedia Definition

Hydroponics is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, expanded clay or coconut husk.

Researchers discovered in the 18th century that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant's water supply artificially, soil is no longer required for the plant to thrive. Almost any terrestrial plant will grow with hydroponics. Hydroponics is also a standard technique in biology research and teaching.

Contents [hide]

1 History 2 Origin

o 2.1 Soilless culture

3 Advantages and disadvantages

o 3.1 Advantages

o 3.2 Disadvantages

4 Techniques

o 4.1 Static solution culture

o 4.2 Continuous-flow solution culture

o 4.3 Aeroponics

o 4.4 Passive sub-irrigation

o 4.5 Ebb and flow or flood and drain sub-irrigation

o 4.6 Run to waste

o 4.7 Deep water culture

o 4.8 Bubbleponics

o 4.9 Fogponics

o 4.10 Rotary

5 Substrates

o 5.1 Expanded clay aggregate

o 5.2 Growstones

o 5.3 Coir

o 5.4 Rice Hulls

o 5.5 Perlite

o 5.6 Pumice

o 5.7 Vermiculite

o 5.8 Sand

o 5.9 Gravel

o 5.10 Wood fibre

o 5.11 Sheep wool

o 5.12 Rock wool

o 5.13 Brick shards

o 5.14 Polystyrene packing peanuts

6 Nutrient solutions

7 Commercial

8 Advancements

9 See also

10 References

11 External links

[edit] HistoryFurther information: Historical hydroculture

The earliest published work on growing terrestrial plants without soil was the 1627 book Sylva Sylvarum by Francis Bacon, printed a year after his death. Water culture became a popular research technique after that. In 1699, John Woodward published his water culture experiments with spearmint. He found that plants in less-pure water sources grew better than plants in distilled water. By 1842, a list of nine elements believed to be essential to plant growth had been compiled, and the discoveries of the German botanists Julius von Sachs and Wilhelm Knop, in the years 1859-65, resulted in a development of the technique of soilless cultivation.[1] Growth of terrestrial plants without soil in mineral nutrient solutions was called solution culture. It quickly became a standard research and teaching technique and is still widely used today. Solution culture is now considered a type of hydroponics where there is no inert medium.

In 1929, William Frederick Gericke of the University of California at Berkeley began publicly promoting that solution culture be used for agricultural crop production.[2] He first termed it aquaculture but later found that aquaculture was already applied to culture of aquatic organisms. Gericke created a sensation by growing tomato vines twenty-five feet high in his back yard in mineral nutrient solutions rather than soil.[3] By analogy with the ancient Greek term for agriculture, geoponics, the science of cultivating the earth, Gericke coined the term hydroponics in 1937 (although he asserts that the term was suggested by W. A. Setchell, of the University of California) for the culture of plants in water (from the Greek hydro-, "water", and ponos, "labour").[1]

Reports of Gericke's work and his claims that hydroponics would revolutionize plant agriculture prompted a huge number of requests for further information. Gericke refused to reveal his secrets claiming he had done the work at home on his own time. This refusal eventually resulted in his leaving the University of California. In 1940, he wrote the book, Complete Guide to Soilless Gardening.

Two other plant nutritionists at the University of California were asked to research Gericke's claims. Dennis R. Hoagland [4] and Daniel I. Arnon [5] wrote a classic 1938 agricultural bulletin, The Water Culture Method for Growing Plants Without Soil,[6] debunking the exaggerated claims made about hydroponics. Hoagland and Arnon found that hydroponic crop yields were no better than crop yields with good-quality soils. Crop yields were ultimately limited by factors other than mineral nutrients, especially light. This research, however, overlooked the fact that hydroponics has other advantages including the fact that the roots of the plant have constant access to oxygen and that the plants have access to as much or as little water as they need. This is important as one of the most common errors when growing is over- and under-

watering; and hydroponics prevents this from occurring as large amounts of water can be made available to the plant and any water not used, drained away, recirculated, or actively aerated, eliminating anoxic conditions, which drown root systems in soil. In soil, a grower needs to be very experienced to know exactly how much water to feed the plant. Too much and the plant will not be able to access oxygen; too little and the plant will lose the ability to transport nutrients, which are typically moved into the roots while in solution. These two researchers developed several formulas for mineral nutrient solutions, known as Hoagland solution. Modified Hoagland solutions are still used today.

One of the early successes of hydroponics occurred on Wake Island, a rocky atoll in the Pacific Ocean used as a refuelling stop for Pan American Airlines. Hydroponics was used there in the 1930s to grow vegetables for the passengers. Hydroponics was a necessity on Wake Island because there was no soil, and it was prohibitively expensive to airlift in fresh vegetables.

In the 1960s, Allen Cooper of England developed the Nutrient film technique. The Land Pavilion at Walt Disney World's EPCOT Center opened in 1982 and prominently features a variety of hydroponic techniques. In recent decades, NASA has done extensive hydroponic research for their Controlled Ecological Life Support System or CELSS. Hydroponics intended to take place on Mars are using LED lighting to grow in different color spectrum with much less heat.

[edit] Origin

[edit] Soilless culture

Gericke originally defined hydroponics as crop growth in mineral nutrient solutions. Hydroponics is a subset of soilless culture. Many types of soilless culture do not use the mineral nutrient solutions required for hydroponics.

Plants that are not traditionally grown in a climate would be possible to grow using a controlled environment system like hydroponics. NASA has also looked to utilize hydroponics in the space program. Ray Wheeler, plant physiologist at Kennedy Space Center’s Space Life Science Lab, believes that hydroponics will create advances within space travel. He terms this as a bioregenerative life support system.[7]

[edit] Advantages and disadvantages

This article contains a pro and con list. Please help improve it by integrating both sides into a more neutral presentation. (November 2012)

[edit] Advantages

Some of the reasons why hydroponics is being adapted around the world for food production are the following:

No soil is needed for hydroponics The water stays in the system and can be reused - thus, lower water costs

It is possible to control the nutrition levels in their entirety - thus, lower nutrition costs

No nutrition pollution is released into the environment because of the controlled system

Stable and high yields

Pests and diseases are easier to get rid of than in soil because of the container's mobility

It is easier to harvest

No pesticide damage

Plants grow healthier

It is better for consumption

Today, hydroponics is an established branch of agronomy. Progress has been rapid, and results obtained in various countries have proved it to be thoroughly practical and to have very definite advantages over conventional methods of horticulture.

There are two chief merits of the soil-less cultivation of plants. First, hydroponics may potentially produce much higher crop yields. Also, hydroponics can be used in places where in-ground agriculture or gardening are not possible.

[edit] Disadvantages

Without soil as a buffer, any failure to the hydroponic system leads to rapid plant death. Other disadvantages include pathogen attacks such as damp-off due to Verticillium wilt caused by the high moisture levels associated with hydroponics and over watering of soil based plants. Also, many hydroponic plants require different fertilizers and containment systems.[8]

[edit] Techniques

The two main types of hydroponics are solution culture and medium culture. Solution culture does not use a solid medium for the roots, just the nutrient solution. The three main types of solution cultures are static solution culture, continuous-flow solution culture and aeroponics. The medium culture method has a solid medium for the roots and is named for the type of medium, e.g., sand culture, gravel culture, or rockwool culture.

There are two main variations for each medium, sub-irrigation and top irrigation[specify]. For all techniques, most hydroponic reservoirs are now built of plastic, but other materials have been used including concrete, glass, metal, vegetable solids, and wood. The containers should exclude light to prevent algae growth in the nutrient solution.

[edit] Static solution culture

In static solution culture, plants are grown in containers of nutrient solution, such as glass Mason jars (typically, in-home applications), plastic buckets, tubs, or tanks. The solution is usually gently aerated but may be un-aerated. If un-aerated, the solution level is kept low enough that enough roots are above the solution so they get adequate oxygen. A hole is cut in the lid of the reservoir for each plant. There can be one to many plants per reservoir. Reservoir size can be increased as plant size increases. A home made system can be constructed from plastic food containers or glass canning jars with aeration provided by an aquarium pump, aquarium airline tubing and aquarium valves. Clear containers are covered with aluminium foil, butcher paper, black plastic, or other material to exclude light, thus helping to eliminate the formation of algae. The nutrient solution is changed either on a schedule, such as once per week, or when the concentration drops below a certain level as determined with an electrical conductivity meter. Whenever the solution is depleted below a certain level, either water or fresh nutrient solution is added, A Mariotte's bottle, or a float valve, can be used to automatically maintain the solution level. In raft solution culture, plants

are placed in a sheet of buoyant plastic that is floated on the surface of the nutrient solution. That way, the solution level never drops below the roots.

[edit] Continuous-flow solution culture

In continuous-flow solution culture, the nutrient solution constantly flows past the roots. It is much easier to automate than the static solution culture because sampling and adjustments to the temperature and nutrient concentrations can be made in a large storage tank that has potential to serve thousands of plants. A popular variation is the nutrient film technique or NFT, whereby a very shallow stream of water containing all the dissolved nutrients required for plant growth is recirculated past the bare roots of plants in a watertight thick root mat, which develops in the bottom of the channel, has an upper surface that, although moist, is in the air. Subsequent to this, an abundant supply of oxygen is provided to the roots of the plants. A properly designed NFT system is based on using the right channel slope, the right flow rate, and the right channel length. The main advantage of the NFT system over other forms of hydroponics is that the plant roots are exposed to adequate supplies of water, oxygen, and nutrients. In all other forms of production, there is a conflict between the supply of these requirements, since excessive or deficient amounts of one results in an imbalance of one or both of the others. NFT, because of its design, provides a system where all three requirements for healthy plant growth can be met at the same time, provided that the simple concept of NFT is always remembered and practised. The result of these advantages is that higher yields of high-quality produce are obtained over an extended period of cropping. A downside of NFT is that it has very little buffering against interruptions in the flow, e.g., power outages. But, overall, it is probably one of the more productive techniques.

The same design characteristics apply to all conventional NFT systems. While slopes along channels of 1:100 have been recommended, in practice it is difficult to build a base for channels that is sufficiently true to enable nutrient films to flow without ponding in locally depressed areas. As a consequence, it is recommended that slopes of 1:30 to 1:40 are used. This allows for minor irregularities in the surface, but, even with these slopes, ponding and water logging may occur. The slope may be provided by the floor, or benches or racks may hold the channels and provide the required slope. Both methods are used and depend on local requirements, often determined by the site and crop requirements.

As a general guide, flow rates for each gully should be 1 liter per minute. At planting, rates may be half this and the upper limit of 2 L/min appears about the maximum. Flow rates beyond these extremes are often associated with nutritional problems. Depressed growth rates of many crops have been observed when channels exceed 12 metres in length. On rapidly growing crops, tests have indicated that, while oxygen levels remain adequate, nitrogen may be depleted over the length of the gully. As a consequence, channel length should not exceed 10–15 metres. In situations where this is not possible, the reductions in growth can be eliminated by placing another nutrient feed halfway along the gully and reducing flow rates to 1 L/min through each outlet.

[edit] AeroponicsMain article: Aeroponics

Aeroponics is a system wherein roots are continuously or discontinuously kept in an environment saturated with fine drops (a mist or aerosol) of nutrient solution. The method requires no substrate and entails growing plants with their roots suspended in a deep air or growth chamber with the roots periodically wetted with a fine mist of atomized nutrients. Excellent aeration is the main advantage of aeroponics.

Aeroponic techniques have proved to be commercially successful for propagation, seed germination, seed potato production, tomato production, leaf crops, and micro-greens.[9] Since inventor Richard Stoner commercialized aeroponic technology in 1983, aeroponics has been implemented as an alternative to water intensive hydroponic systems worldwide.[10] The limitation of hydroponics is the fact that 1 kg of water can only hold 8 mg of air, no matter whether aerators are utilized or not.

Another distinct advantage of aeroponics over hydroponics is that any species of plants can be grown in a true aeroponic system because the micro environment of an aeroponic can be finely controlled. The limitation of hydroponics is that only certain species of plants can survive for so long in water before they become waterlogged. The advantage of aeroponics is that suspended aeroponic plants receive 100% of the available oxygen and carbon dioxide to the roots zone, stems, and leaves,[11] thus accelerating biomass growth and reducing rooting times. NASA research has shown that aeroponically grown plants have an 80% increase in dry weight biomass (essential minerals) compared to hydroponically grown plants. Aeroponics used 65% less water than hydroponics. NASA also concluded that aeroponically grown plants requires ¼ the nutrient input compared to hydroponics. Unlike hydroponically grown plants, aeroponically grown plants will not suffer transplant shock when transplanted to soil, and offers growers the ability to reduce the spread of disease and pathogens. Aeroponics is also widely used in laboratory studies of plant physiology and plant pathology. Aeroponic techniques have been given special attention from NASA since a mist is easier to handle than a liquid in a zero gravity environment.

[edit] Passive sub-irrigationMain article: Passive hydroponics

Passive sub-irrigation, also known as passive hydroponics or semi-hydroponics, is a method wherein plants are grown in an inert porous medium that transports water and fertilizer to the roots by capillary action from a separate reservoir as necessary, reducing labour and providing a constant supply of water to the roots. In the simplest method, the pot sits in a shallow solution of fertilizer and water or on a capillary mat saturated with nutrient solution. The various hydroponic media available, such as expanded clay and coconut husk, contain more air space than more traditional potting mixes, delivering increased oxygen to the roots, which is important in epiphytic plants such as orchids and bromeliads, whose roots are exposed to the air in nature. Additional advantages of passive hydroponics are the reduction of root rot and the additional ambient humidity provided through evaporations.

[edit] Ebb and flow or flood and drain sub-irrigationMain article: Ebb and flow

In its simplest form, there is a tray above a reservoir of nutrient solution. Either the tray is filled with growing medium (clay granules being the most common) and planted directly or pots of medium stand in the tray. At regular intervals, a simple timer causes a pump to fill the upper tray with nutrient solution, after which the solution drains back down into the reservoir. This keeps the medium regularly flushed with nutrients and air. Once the upper tray fills past the drain stop, it begins recirculating the water until the timer turns the pump off, and the water in the upper tray drains back into the reservoirs.

[edit] Run to waste

In a run to waste system, nutrient and water solution is periodically applied to the medium surface. This may be done in its simplest form, by manually applying a nutrient-and-water solution one or more times per day in a container of inert growing media, such as rockwool, perlite, vermiculite, coco fibre, or sand. In a slightly more complex system, it is automated

with a delivery pump, a timer and irrigation tubing to deliver nutrient solution with a delivery frequency that is governed by the key parameters of plant size, plant growing stage, climate, substrate, and substrate conductivity, pH, and water content.

In a commercial setting, watering frequency is multi factorial and governed by computers or PLCs.

Commercial hydroponics production of large plants like tomatoes, cucumber, and peppers use one form or another of run to waste hydroponics.

In environmentally responsible uses, the nutrient rich waste is collected and processed through an on site filtration system to be used many times, making the system very productive.[12]

[edit] Deep water cultureMain article: Deep water culture

The hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich, oxygenated water. Traditional methods favor the use of plastic buckets and large containers with the plant contained in a net pot suspended from the centre of the lid and the roots suspended in the nutrient solution. The solution is oxygen saturated from an air pump combined with porous stones. With this method, the plants grow much faster because of the high amount of oxygen that the roots receive.[13]

[edit] Bubbleponics

"Bubbleponics" is the art of delivering highly oxygenated nutrient solution direct to the root zone of plants. While Deep Water Culture involves the plant roots hanging down into a reservoir of water below, the term Bubbleponics describes a top-fed Deep Water Culture (DWC) hydroponic system. In this method, the water is pumped from the reservoir up to the roots (top feeding). The water is released over the plant's roots and then runs back into the reservoir below in a constantly recirculating system. As with Deep Water Culture, there is an airstone in the reservoir that pumps air into the water via a hose from outside the reservoir. The airstone helps add oxygen to the water. Both the airstone and the water pump run 24 hours a day.

The biggest advantages with Bubbleponics over Deep Water Culture involve increased growth during the first few weeks. With Deep Water Culture, there is a time where the roots have not reached the water yet. With Bubbleponics, the roots get easy access to water from the beginning and will grow to the reservoir below much more quickly than with a Deep Water Culture system. Once the roots have reached the reservoir below, there is not a huge advantage with Bubbleponics over Deep Water Culture. However, due to the quicker growth in the beginning, a few weeks of grow time can be shaved off.[14]

[edit] FogponicsMain article: Fogponics

Fogponics Fogponics is an advanced form of aeroponics which uses water in a vaporised form to transfer nutrients and oxygen to enclosed suspended plant roots. Using the same general idea behind aeroponics except fogponics uses a 5-10 micron mist within the rooting chamber and as use for a foliar feeding mechanism.

[edit] Rotary

A rotary hydroponic garden is a style of commercial hydroponics created within a circular frame which rotates continuously during the entire growth cycle of whatever plant is being grown.

While system specific vary, systems typically rotate once per hour, giving a plant 24 full turns within the circle each 24 hour period. Within the center of each rotary hydroponic garden is a high intensity grow light, designed to simulate sunlight, often with the assistance of a mechanized timer.

Each day, as the plants rotate, they are periodically watered with a hydroponic growth solution to provide all nutrient necessary for robust growth. Due to the plants continuous fight against gravity plants typically mature much more quickly than when grown in soil or other traditional hydroponic growing systems. Due to the small foot print a rotary hydroponic system has, it allows for more plant material to be grown per sq foot of floor space than other traditional hydroponic systems.

[edit] Substrates

One of the most obvious decisions hydroponic farmers have to make is which medium they should use. Different media are appropriate for different growing techniques.

[edit] Expanded clay aggregateMain article: Expanded clay aggregate

Expanded clay pebbles.

Baked clay pellets, are suitable for hydroponic systems in which all nutrients are carefully controlled in water solution. The clay pellets are inert, pH neutral and do not contain any nutrient value.

The clay is formed into round pellets and fired in rotary kilns at 1,200 °C (2,190 °F). This causes the clay to expand, like popcorn, and become porous. It is light in weight, and does not compact over time. The shape of an individual pellet can be irregular or uniform depending on brand and manufacturing process. The manufacturers consider expanded clay to be an ecologically sustainable and re-usable growing medium because of its ability to be cleaned and sterilized, typically by washing in solutions of white vinegar, chlorine bleach, or hydrogen peroxide (H2O2), and rinsing completely.

Another view is that clay pebbles are best not re-used even when they are cleaned, due to root growth that may enter the medium. Breaking open a clay pebble after a crop has been grown will reveal this growth.

[edit] Growstones

Growstones, made from glass waste, have both more air and water retention space than perlite and peat. This aggregate holds more water than parboiled rice hulls.[15]

[edit] Coir

Coco Peat, also known as coir or coco, is the leftover material after the fibres have been removed from the outermost shell (bolster) of the coconut. Coir is a 100% natural grow and flowering medium. Coconut Coir is colonized with trichoderma Fungi, which protects roots and stimulates root growth. It is extremely difficult to over water coir due to its perfect air-to-water ratio, plant roots thrive in this environment, coir has a high cation exchange, meaning it can store unused minerals to be released to the plant as and when it requires it. Coir is available in many forms, most common is coco peat, which has the appearance and texture of soil but contains no mineral content.

[edit] Rice Hulls

Parboiled rice hulls (PBH) decay over time. Rice hulls allow drainage,[16] and even retain less water than growstones.[15] A study showed that rice hulls didn't affect the effects of plant growth regulators. [16] Rice hulls are an agricultural byproduct that would otherwise have little use.

[edit] Perlite

Perlite is a volcanic rock that has been superheated into very lightweight expanded glass pebbles. It is used loose or in plastic sleeves immersed in the water. It is also used in potting soil mixes to decrease soil density. Perlite has similar properties and uses to vermiculite but, in general, holds more air and less water. If not contained, it can float if flood and drain feeding is used. It is a fusion of granite, obsidian, pumice and basalt. This volcanic rock is naturally fused at high temperatures undergoing what is called "Fusionic Metamorphosis".

[edit] Pumice

Like perlite, pumice is a lightweight, mined volcanic rock that finds application in hydroponics.

[edit] Vermiculite

Like perlite, vermiculite is a mineral that has been superheated until it has expanded into light pebbles. Vermiculite holds more water than perlite and has a natural "wicking" property that can draw water and nutrients in a passive hydroponic system. If too much water and not enough air surrounds the plants roots, it is possible to gradually lower the medium's water-retention capability by mixing in increasing quantities of perlite.

[edit] Sand

Sand is cheap and easily available. However, it is heavy, does not hold water very well, and it must be sterilized between use.

[edit] Gravel

The same type that is used in aquariums, though any small gravel can be used, provided it is washed first. Indeed, plants growing in a typical traditional gravel filter bed, with water circulated using electric powerhead pumps, are in effect being grown using gravel hydroponics. Gravel is inexpensive, easy to keep clean, drains well and will not become waterlogged. However, it is also heavy, and, if the system does not provide continuous water, the plant roots may dry out.

[edit] Wood fibre

Wood fibre, produced from steam friction of wood, is a very efficient organic substrate for hydroponics. It has the advantage that it keeps its structure for a very long time. Wood fibre has been shown to reduce the effects of "plant growth regulators."[16]

[edit] Sheep wool

Wool from shearing sheep is a little-used yet promising renewable growing medium. In a study comparing wool with peat slabs, coconut fibre slabs, perlite and rockwool slabs to grow cucumber plants, sheep wool had a greater air capacity of 70%, which decreased with use to a comparable 43%, and water capacity that increased from 23% to 44% with use. Using sheep wool resulted in the greatest yield out of the tested substrates, while application of a biostimulator consisting of humic acid, lactic acid and Bacillus subtilis improved yields in all substrates.[17]

[edit] Rock wool

Rock wool (mineral wool) is the most widely used medium in hydroponics. Rock wool is an inert substrate suitable for both run to waste and recirculating systems. Rock wool is made from molten rock, basalt or 'slag' that is spun into bundles of single filament fibres, and bonded into a medium capable of capillary action, and is, in effect, protected from most common microbiological degradation. Rock wool has many advantages and some disadvantages. The latter being the possible skin irritancy (mechanical) whilst handling (1:1000). Flushing with cold water usually brings relief. Advantages include its proven efficiency and effectiveness as a commercial hydroponic substrate. Most of the rock wool sold to date is a non-hazardous, non-carcinogenic material, falling under Note Q of the European Union Classification Packaging and Labeling Regulation (CLP).[citation needed]

[edit] Brick shards

Brick shards have similar properties to gravel. They have the added disadvantages of possibly altering the pH and requiring extra cleaning before reuse.

[edit] Polystyrene packing peanuts

Polystyrene packing peanuts are inexpensive, readily available, and have excellent drainage. However, they can be too lightweight for some uses. They are used mainly in closed-tube systems. Note that polystyrene peanuts must be used; biodegradable packing peanuts will decompose into a sludge. Plants may absorb styrene and pass it to their consumers; this is a possible health risk.

[edit] Nutrient solutionsMain article: Plant nutrition

Plant nutrients used in hydroponics are dissolved in the water and are mostly in inorganic and ionic form. Primary among the dissolved cations (positively charged ions) are Ca2+ (calcium), Mg2+ (magnesium), and K+ (potassium); the major nutrient anions in nutrient solutions are NO−3 (nitrate), SO2−4 (sulfate), and H2PO−4 (dihydrogen phosphate).

Numerous 'recipes' for hydroponic solutions are available. Many use different combinations of chemicals to reach similar total final compositions. Commonly used chemicals for the macronutrients include potassium nitrate, calcium nitrate, potassium phosphate, and magnesium sulfate. Various micronutrients are typically added to hydroponic solutions to supply essential elements; among them are Fe (iron), Mn (manganese), Cu (copper), Zn (zinc), B (boron), Cl (chlorine), and Ni (nickel). Chelating agents are sometimes used to keep Fe soluble. Many variations of the nutrient solutions used by Arnon and Hoagland (see above) have been styled 'modified Hoagland solutions' and are widely used. Variation of different mixes throughout the plant life-cycle, further optimizes its nutritional value.[18] Plants will change the composition of the nutrient solutions upon contact by depleting specific nutrients more rapidly than others, removing water from the solution, and altering the pH by excretion of either acidity or alkalinity.[19] Care is required not to allow salt concentrations to become too high, nutrients to become too depleted, or pH to wander far from the desired value.

Although pre-mixed concentrated nutrient solutions are generally purchased from commercial nutrient manufacturers by hydroponic hobbyists and small commercial growers, several tools exists to help anyone prepare their own solutions without extensive knowledge about chemistry. The free and open source tools HydroBuddy[20] and HydroCal[21] have been created by professional chemists to help any hydroponics grower prepare their own nutrient solutions. The first program is available for Windows, Mac and Linux while the second one can be used through a simple Java interface. Both programs allow for basic nutrient solution preparation although HydroBuddy provides added functionality to use and save custom substances, save formulations and predict electrical conductivity values.

The well-oxygenated and enlightened environment promotes the development of algae. It is therefore necessary to wrap the tank with black film obscuring all light.

Organic hydroponics uses the solution containing microorganisms. In organic hydroponics, organic fertilizer can be added in the hydroponic solution because microorganisms degrade organic fertilizer into inorganic nutrients. In contrast, conventional hydroponics cannot use organic fertilizer because organic compounds in the hydroponic solution show phytotoxic effects.

[edit] Commercial

Some commercial installations use no pesticides or herbicides, preferring integrated pest management techniques. There is often a price premium willingly paid by consumers for produce that is labelled "organic". Some states in the USA require soil as an essential to obtain organic certification. There are also overlapping and somewhat contradictory rules established by the US Federal Government, so some food grown with hydroponics can be certified organic.

Hydroponics also saves water; it uses as little as 1⁄20 the amount as a regular farm to produce the same amount of food. The water table can be impacted by the water use and run-off of chemicals from farms, but hydroponics may minimize impact as well as having the advantage that water use and water returns are easier to measure. This can save the farmer money by

allowing reduced water use and the ability to measure consequences to the land around a farm.

To increase plant growth, lighting systems such as metal-halide lamp for growing stage only or high-pressure sodium for growing/flowering/blooming stage are used to lengthen the day or to supplement natural sunshine if it is scarce. Metal halide emits more light in the blue spectrum, making it ideal for plant growth but is harmful to unprotected skin and can cause skin cancer. High-pressure sodium emits more light in the red spectrum, meaning that it is best suited for supplementing natural sunshine and can be used throughout the growing cycle. However, these lighting systems require large amounts of electricity to operate, making efficiency and safety very critical.

The environment in a hydroponics greenhouse is tightly controlled for maximum efficiency, and this new mindset is called soil-less/controlled-environment agriculture (CEA). With this growers can make ultra-premium foods anywhere in the world, regardless of temperature and growing seasons. Growers monitor the temperature, humidity, and pH level constantly.

Hydroponics have been used to enhance vegetables to provide more nutritional value. A hydroponic farmer in Virginia has developed a calcium and potassium enriched head of lettuce, scheduled to be widely available in April 2007. Grocers in test markets have said that the lettuce sells "very well", and the farmers claim that their hydroponic lettuce uses 90% less water than traditional soil farming.[22]

[edit] Advancements

With pest problems reduced, and nutrients constantly fed to the roots, productivity in hydroponics is high, although plant growth can be limited by the low levels of carbon dioxide in the atmosphere, or limited light exposure. To increase yield further, some sealed greenhouses inject carbon dioxide into their environment to help growth (CO2 enrichment), add lights to lengthen the day, or control vegetative growth, etc.