Umbo - A blunt or rounded projection arising from a surface, as on a pine cone scale.

Uneven-aged - A condition of forest or stand that contains intermingled trees that differ markedly in age. By convention, a minimum range of 10 to 20 years is generally accepted, though with rotations of not less than 100 years, 25 percent (USA) of the rotation may be the minimum.

Ultraviolet - Light with very short wave lengths, out of the visible spectrum

Unicellular - Organisms consisting a single cell. This is true of bacteria.

USDA (Acronym) - United States Department of Agriculture. The governmental division handles all things related to biocontrol and IPM. This includes authorizing importation.

Variety - A subdivision of a species, usually separated geographically from the typical, having one or more heritable, morphological characteristics which differ from the typical even when grown under the same environmental conditions; a morphological variant.

Vent - Opening such as a window or door that allows the circulation of fresh air.

Ventilation - Circulation of fresh air, fundamental to healthy indoor garden. An exhaust fan creates excellent ventilation.

Vertical - Up and down; perpendicular to the horizontal.

Vascular - By which means a living organism moves or translocates life-giving fluids through its system or body.

Vector - An organism which produces a pathogenic fungus. I think this also pertains to an insect that can also transmit said fungus during its feeding activities.

Vermiculite - This is sterile — immediately post manufacture that is — and made of heat-expanded mica. The layers trap moisture that when heated expand and form a soft, lightweight, neutral material.

Vermiculture - The act of rearing or producing worms for fishing or composting. Typically the latter as it pertains to this material.

Virus - The meaning of this word in this text is the same as it means in your dictionary. The viral strains in this case target certain plants. Just as small, just as deadly.

Viviparously - Quite simply it is live birth. Devloping inside the mother rather than inside an egg. Humans are vivaparous.

VAM - (Vesicular arbuscular mycorrhiza) a type of soil fungus infecting the roots of some plants and assisting in the uptake of phosphorus and other immobile soil nutrients.

Verticillium - Any of several fungal diseases that afflict plants; commonly called wilt. See also Fusarium.

Volatilisation - Process by which certain soluble soil nutrients are changed from solid or aqueous forms to gaseous forms and are lost from the soil to the atmosphere e.g. ammonium (NH,') to ammonia gas (NH3).

Wetting agent - Compound that reduces the droplet size and lowers the surface tension of the water, making it wetter.

Liquid concentrate dish soap is a good wetting agent if it is biodegradable,

Wick - Part of a passive hydroponic system using a wick suspended in the nutrient solution, the nutrients pass up the wick and are absorbed by the medium and roots.

W3C (Acronym): Web Related - This is the organization being the created, implementation, organization, and the maintenance and creation of web standards.

WPS (Acronym) - Worker Protection Standard. This self-explanatory standard was created by the EPA. It spawned new acronyms such as REI and PPE.

Xeriscape - A desert-dry garden regulated hot/dry greenhouse environment, or extremely water-conservative landscape planting.

XHTML (acronym): Web-Related - Extensible HyperText Mark-up Language. A type of text coding capable of being read and displayed by web browsing devices and other user agents and assistive technologies. This is an extensible form of HTML.

Xerophyte - A plant that is adapted to dry or and habitats.

Yield - In my glossary it denotes a quantified output whether it be crop- or bug-associated.

Zzzz. - Denotes sleep, which is something you may need if you've been reading this site's content for more an hour more or less.

See “Quiescence” Zinc (Zn) - Like copper and manganese, zinc is linked to chlorophyll synthesis.