magnesium deficiency n - plant disease resulting from lack of magnesium or excesses of Ca or Cl; characterized by chlorosis between the veins of the leaves at the top of the plant, leading to necrosis and curling of the blades
marijuana n - A preparation made from the dried flower clusters and leaves of the cannabis plant, usually smoked or eaten to induce euphoria
mealy bugs n - scale-like, 2-7 mm oblong plant-eating insects, coated with a powdery, waxy secretion, that live in colonies and attack the cannabis plant at the stem joints
mercury vapor n - light fixture that produces light by arcing electricity through mercury and a small amount of argon gas
metal halide n - light fixture that produces light by passing or arcing electricity through vaporized argon gas, mercury, thorium iodide, sodium iodide, and scandium iodide within a quartz arc tube
mold n - a fungus that produces a superficial growth on various kinds of damp or decaying organic matter; plant disease characterized by mushy, rotting spots on the leaves and stems that can be purple, black, or brown in color, causes necrosis of plant tissue, weakening of stems and affected tissue, and death, treated by lowering humidity and application of fungicide, such as copper, lime, or sulfur, to the affected area
monoecious n - A plant that has both male and female flowers on the same plant. Marijuana can be monoecious sometimes but is not favourable.
morphology n - the branch of biology that deals with the structure of animals and plants; The form and structure of an organism or one of its parts
mylar n - a thin, highly reflective polyester film
myrcene n - essential oil of the cannabis plant partly responsible for its aroma | 
