Back to Glossary A - Z

Lap sealant A clear sealing material forced into the space formed between two overlapping panes of glass. (Nelson, 2003)

Larva The immature, wingless, and often wormlike form in which some insects hatch from the egg and in which they remain through increase in size and other minor changes until they assume the pupa or chrysalis stage. (Nelson, 2003)

Leaching percentage The percentage of water or nutrient solution applied to a pot or bench of root substrate that drains from the bottom of that container. (Nelson, 2003)

Lean-to greenhouse A greenhouse built against the side of another structure such that is has only one sloping roof. (Nelson, 2003)

Loam A textural class name for soils having reasonably balanced amounts of sand, silt, and clay. Loam soils can contain 7-28% clay, 28-50% silt, and less than 52% sand. (Nelson, 2003)

Long-night (short-day) plant A plant that undergoes photoperiodic response, such as flowering, only when the night length is greater than a critical length. (Nelson, 2003)

Lumen The unit of light equal to the light emitted in a unit solid angle by a uniform point source of 1 international candle. (Nelson, 2003)

Lux The international unit of illumination, being the direct illumination on a surface that is everywhere 1 meter from a uniform point source of 1 international candle. It is equal to 1 lumen per square meter, or 0.0929 foot-candles. (Nelson, 2003)