Greenhouse Management
Glossary
C
C:N RATIO –The ratio of carbon to nitrogen in organic materials. Materials with a high C:N ratio (high in carbon) are good bulking agents in compost piles, while those with a low C:N ratio (high in nitrogen) are good energy sources.
CALCAREOUS SOIL – A soil in which finely divided lime is naturally distributed; it usually has a pH between 7 and slightly more than 8.
CALCIUM CARBONATE – Calcium carbonate is a chemical compound found in rocks as the minerals calcite and aragonite (most notably as limestone, which contains both of those minerals) and is the active ingredient in agricultural lime.
CAPILLARY MAT – A fiber mat that is used to distribute water to potted plants by capillary action.
CARBON DIOXIDE (CO2) – A naturally occurring compound that is integral for life functions on Earth, found in gaseous form at surface temperatures. All animals, plants, fungi, and microorganisms produce CO2 during respiration. Plants use it during photosynthesis. Carbon dioxide is also generated as a natural by-product of the decomposition of organic matter and the combustion of fossil fuels or vegetative matter, among other chemical processes.
CARRIER – The primary material used to allow a pesticide to be dispersed effectively; for example, the talc in a dust formulation, the water mixed with a wettable powder before a spray application, or the air that disperses the pesticide in an air blast application.
CATION – A positively charged ion such as calcium (Ca2+) or ammonium (NH4+).
CATION EXCHANGE CAPACITY (CEC) – The amount of negative charge that exists on humus and clays, allowing them to hold on to positively charged chemicals (cations).
CHELATE – A molecule that uses more than one bond to attach strongly to certain elements such as iron (Fe2+) and zinc (Zn2+). These elements may later be released from the chelate and used by plants.
CHEMICAL NAME – Scientific name of the active ingredient(s) found in the formulated product. The name is derived from the chemical structure of the active ingredient.
CHEMIGATION – The process of applying chemicals (fertilizers, insecticides, herbicides, etc.) to crops or soil through an irrigation system with the water.
COCONUT FIBER – Coconut fiber, also called coir, is rapidly becoming one of the most popular growing mediums in the world and may soon be the most popular.
COLD FRAME – A cold frame is a transparent-roofed enclosure, built low to the ground, used to protect plants from adverse weather, primarily excessive cold or wet. The transparent top admits sunlight and prevents heat escape via convection that would otherwise occur, particularly at night.
COLD STORAGE – The treatment given to plants and bulbs to ca use certain internal chemical changes that enable them to respond to forcing treatments.
COMPOST – The product of a managed process through which microorganisms break down plant and animal materials into more available forms suitable for application to the soil. Compost must be produced through a process that combines plant and animal materials with an initial C:N ratio of between 25:1 and 40:1.
CONTROLLED RELEASE FERTILIZER – Also called Time Release Fertilizer. Fertilizer comes in pellets and is an improved version of Slow Release Fertilizer. Fertilizer is released based on soil temperature itself (not microbe action) and tends to be more exact than Slow Release Fertilizer.
CONTROLLER – An irrigation system controller regulates when the electric valves in the system opens and closes. They can also be called a timer as they can be set up on a schedule to deliver just the right amount of water to the lawn or garden at particular days and times. Controllers send low-voltage electric impulses to the valve to open or close it.
CONVECTION HEAT LOSS – Loss of heat from the greenhouse as it moves in air convection currents to the greenhouse covering, then through the covering by conduction, and finally away from the outside of the covering.
CROWN – The base of the plant, where the stem and root meet.
CULTIVAR – A cultivated variety or strain that originated and has persisted under human cultivation.
