Greenhouse Management
Glossary
L
LARVA (larvae is plural) – The immature form of an insect that undergoes complete metamorphosis. Different from the adult in form, a caterpillar for example. The newly hatched, wingless, often wormlike form of many insects before metamorphosis.
LATH HOUSE – A structure covered with wood or metal slats used to protect plants from a high light intensity.
LEAN-TO – Structure which is attached to another building along its ridgeline.
LIGHT EMITTING DIODE (LED) – LEDs are solid-state semiconductor devices that produce narrow spectrum light when voltage is applied. Different semiconductor materials can produce different light spectrum. Commercially available light spectra which are relevant for plant growth and development range from 215 to 910 nm which includes: ultraviolet, violet, blue, green, yellow, orange, red, far red, and near infrared.
LIGHT METER – A meter used to measure light intensity usually in foot candles.
LIME OR LIMESTONE – A mineral consisting of calcium carbonate (CaCO3) that can neutralize acids and is commonly applied to acid soils.
LOUVER – A mechanically or electrically operated unit that opens and closes to allow air to enter or exit a green house.
LUMEN – The unit of light equal to the light emitted in a unit solid angle by a uniform point source of one international candle.
LUX – The international unit of illumination, being the direct illumination on a surface that is everywhere 1 meter from a uniform point source of one international candle. It is equal to one lumen per square meter, or 0.0929 foot-candles.
