The process of water loss by plants is a simple physical process of heat exchange. This is proven by the coolness of your bare skin when you walk out of the water, and the heat rising from the stove when you boil water. Plants generally differ little in how much water they use. Forests use a little more water than grass lands, hence forests generally occur in moist regions, and grasslands in arid regions. Except for cacti and other succulents, most plants use about the same amount of water. The main difference is that some plants need more irrigation, while other plants, woody plants especially, are better at tapping the underground reserves.

Grass needs water, but how much? Soils with good water holding capacity, such as AquaGreen, provide more water reserve for the roots than sandy soils. Turf grown near heat sources, such as pavement, uses more water, while turf under trees uses less water. The process of water loss by plants is a simple physical process of heat exchange. Actual results which you might experience in a lawn will vary according to microenvironment, e.g., the presence of trees, exposure to the wind, the quality of your soil, and the condition of the turf. Grass which has been fertilized recently with highly soluble fertilizer often wilts quickly. Technically, St. Augustine grass uses only a little more water than other, drought avoidant grasses such as Bermuda grass and Bahia grass. What probably lends to the severity of drought damage in St. Augustine grass is the exposure of the horizontal above-ground stems ("stolons") to desiccation.

Any new growth in grasses must come from the stems. Once the stems have dried excessively, the turfgrass plant can make no more leaves, roots, or stems. Since St Augustine grass is the one grass that requires the maximum moisture to maintain its health, we will focus on that one grass knowing that if AquaGreen works on St Augustine turf, there is no doubt it will also work on Bermuda, Zoysia, Bahia, Fescue, etc.

A five year Study was performed on St Augustine Grass to determine its evapotransporation rate.* How much water was emitted into the atmosphere from the plant leaf surfaces? It was shown over a 5 year period this number was 43 inches of rain per year. This equates out to ( 624 gal * 43 inches) = 26,832 gallons per 1,000 sq ft.

How many inches of rainfall occur in each region of the country will dictate the amount of irrigation needed to sustain a healthy plant. Lets look at the rainfall averages in Texas.

As you can see from the above chart, the City of Houston receives more rainfall than is necessary to keep St Augustine Grass thriving. Each of the other major Cities in Texas still require annual irrigation to keep their St Augustine turf from drought kill.

· Stewart, E. H. and W. C. Mills. 1967. Effect of depth of water table and plant density on evapotranspiration rate in southern Florida. Trans. ASAE 10:746-747.