Elbs unit 1 b491 lesson 11 glasshouse crops

ELBS Unit 1 B491 Lesson 11

Greenhouses. LOs1. know how a glasshouse crop is grown

(E-D) 2. understand how a glasshouse

environment is controlled (D-C)

What we can control in a glasshouse?

Pick 5 from:Light

Sex of pests

Temperature

Humidity

Water

Altitude

Bank rate

Nutrients

What we can control in a glasshouse?

□Temperature□Light□Water□Nutrients□AirThis means that you are not limited by theconditions outside and the growing season canbe lengthened. This may mean that a number

ofcrops can be grown each year.

Heating

Heaters can be connected to a thermostat that turns them on when the temperature drops below a certain level and turns them off when the temperature is too high.

Heating is used in the winter and spring to allow plants to germinate quicker than outdoor plants.

A heated propagator means that the whole greenhouse does not have to be heated. It works like amini greenhouse.

Making a propagator

Use a seed tray and fill it with compost.Plant seeds in the compost and water generously.Cover the propagator with a plastic bag or clear plastic

film.Place the propagator in a warm place, such as on a warmwindow sill.Good seeds to use are peas,

beans, melons, or marrows.

More on greenhouse practice

Soil warming cables can be put under the soil to heat theunit. Cuttings can be put straight into compost.A plastic cover helps keep the air moist.Heaters can be used in conjunction with propagators, butregard needs to be made for safety and environmental cost.VentilationOften done with windows.Plants need oxygen for respiration and carbon dioxide for photosynthesis

Irrigation and lighting

Plants need continuous water to keep leaves turgid. Mist propagators have a fine spray of water that switches on when plants become dry. Humid air reduces transpiration and thus water loss. Cuttings lack roots are cannot replace lost water.

Capillary matting

Capillary matting is a means of self-watering. One end of the roll of matting is placed in a

watertrough. The water is drawn along the matting

andup through the pot bases by capillary action.

Seep hosesThese are hoses, connected to a supply, thatslowly leak the water in them to provide a

constantsupply of water to the plants.

Lighting

Artificial light can be provided in greenhouses to make

sure that plants have extra hours of light for growth.

Fluorescent lights are often linked to a time switch.

ELBS Unit 1 B491 Lesson 11

Greenhouses. LOs1. know how a glasshouse crop is

grown 2. understand how a glasshouse

environment is controlled