Greenhouse Management

Glossary

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SAWDUST – The species of tree from which sawdust is derived largely determines its quality and value for use in a growing media.

SCION – The portion of a plant or cultivar that is grafted onto a separate rootstock, consisting of a piece of shoot with dormant buds that will produce the stem and branches.

SEEDLING – A young plant grown from seed.

SELF-POLLINATING – Plants that do not require pollen from another plant in order to produce fruit.

SINGLE LAYER – Cover or glazing composed of one layer of rigid or flexible film material.

SINGLE-SPAN – An independent, single-bay structure, separate from adjacent structures.

SLOW RELEASE FERTILIZER – Fertilizer that comes in pellets and is slowly released based largely on microbes which are more or less active based on soil temperatures.

SLURRY – Thin, watery mixture, such as liquid mud, cement, etc. Fungicides and some insecticides are applied to seeds as slurries to produce thick coating and reduce dustiness.

SOLENOID VALVE – An electrically activated valve that controls the flow of gases or liquids. Such valves can be activated by a time clock to control the flow of water in automated greenhouse watering systems.

SOLUBLE POWDER – A finely ground, solid material that will dissolve in water or some other liquid carrier.

SOLVENT – A liquid, such as water, kerosene, xylene, or alcohol, that will dissolve a pesticide (or other substance) to form a solution.

SOLUBLE – Able to be dissolved in another substance, usually a liquid.

SPHAGNUM MOSS – Sphagnum moss is the dehydrated remains of acid-bog plants from the genus Sphagnum. 

SPREADER – Ingredient added to spray mixture to improve contact between pesticide and plant surface.

STATIC WATER PRESSURE – The water pressure as measured when the water is not moving. When measuring the static water pressure all the water outlets on the pipe must be closed. 

STEAM PASTEURIZATION – The use of steam to pasteurize the soil, pots, tools, and other materials used in greenhouses.

STICKER – Ingredient added to spray or dust to improve its adherence to plants.

STOCK PLANTS – Plants maintained to produce vegetative propagation material (cuttings).

SUBIRRIGATION – Flats and/or pots are watered from the bottom, and the water rises by capillary action.

SUCKER – Undesirable growth coming from the rootstock of a grafted plant.

SURFACTANT – Material that can greatly reduce the surface tension of water when used in very low concentrations. Soap is a simple surfactant. Pesticide surfactants are nonionic (do not ionize, but will have a slight electrostatic charge due to the polarity of dissimilar atoms in the molecule), anionic (ionized, have a strong negative charge), or cationic (ionized, have a strong positive charge).

SUSPENSION – A substance that contains undissolved particles mixed throughout a liquid.