Greenhouse Ventilation Flashcards
Describe passive ventilation in a greenhouse
Traditional method
open roof vents so hot air inside rises and exits.
Side vents can be opened to lower temps of crop.
Using both side and top openings achieves a ‘chimney effect’
Number and size of vents determined by floor area
If windy, only open vents on leeward side to prevent turbulence.
how do you achieve ventilation in garden frames? (cold frames?)
lift up one side and prop up.
how do vents work if they have automatic sensing equipment?
an oil filled piston opens vents.
what is active ventilation?
This is done by exhaust or extraction fans that move the air across the house - widely used in commercial greenhouses.
what can you use as a shelterbelt/windbreak in a greenhouse?
paraweb - thick plastic netting.
it assists in reducing cold winds
why do we arm soil/growing media in greenhouses?
it ensures root growth and aids seed germination/root development.
what method can be used to warm soil in a greenhouse?
soil warming cables
how do soil warming cables work?
they are linked to a thermostat
they run along the base of GH in the growing media
they provide heat at a low cost.
