Warm-Season Turfgrass - Turfgrass species whose optimum growth occurs during the warmer periods (80º - 95º F) of the growing season.

Water Insoluble Nitrogen (WIN) - That fraction of nitrogen contained in fertilizer not considered to soluble in 25^o C. water. It is generally a measure of how much of the nitrogen is considered to show the slow release characteristic.

Water Soluble Nitrogen (WSN) - That fraction of nitrogen contained in fertilizer considered to be soluble in 25^o C. water. It is generally a measure of the quick-release nitrogen contained in the fertilizer. Unlike WIN this is usually not expressed on a fertilizer package. Unless stated otherwise, the difference between the WIN and total nitrogen contained in the package is WSN.

Watering-In - Water applied to turf immediately after the application of some pesticides or fertilizers to dissolve and/or move materials into the soil.

Waterlogging - Soil saturated with water usually for an extended period of time and resulting in temporary anaerobic conditions.

Wear - The accumulative (and usually deleterious) effects of traffic on a turf area. Most often a problem on sports fields.

Weed - An undesired, uncultivated plant growing in a manner so as to adversely compete with desirable plants for water, light and nutrients, or destroy aesthetic qualities of a lawn.