Greenhouse Management
Glossary
M
MACRONUTRIENT – A nutrient that a plant needs in relatively large amounts. Essential macronutrients are nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S).
MANIFOLD – Irrigation valves arranged in a valve box that control water flow to multiple zones.
MANURE – Feces, urine, other excrement, and bedding produced by animal that has not been composted.
MEDIUM – The term used to describe the “soil” in which plants are grown; the plural of medium is media.
METAL HALIDE LIGHTS – Metal halide bulbs produce an abundance of light in the blue spectrum. This color of light promotes plant growth and is excellent for green leafy growth and keeping plants compact. It is the best type of light to be used as a primary light source (if no or little natural sunlight is available).
MICRONUTRIENT – Nutrients required by plants in only small or trace amounts. Boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn) are considered micronutrients.
MICRO-TUBING – Also called spaghetti tubing. This small, flexible tubing is ¼ inch diameter and is used extensively as a lateral line from ½ inch or larger mainline tubing. Micro tubing is often used with drippers, misters or sprayers and comes in flexible vinyl and polyethylene.
MINERALIZATION –The process by which plant nutrients in soil organic matter are released by microbial action into soluble or available forms, which plants can absorb. Nitrogen mineralization is ammonification. For example, organic forms of nitrogen are converted to nitrate.
MIST COOLING – Evaporative cooling by spraying tiny water droplets into the greenhouse.
MULTI-BAY – Construction where modular structural units are connected at the gutters to cover large ground areas.
