THE KEY FACTORS affecting the green color of turfgrass, beyond its natural color, are Nitrogen, Sulfur, and Iron [Manganese plays a minor role]. For most turf grasses, the 'ultimate' dark green color is achieved with Nitrogen fertilizer. Yet, achieving that 'ultimate' green with excessive Nitrogen can carry a heavy price - in added fertilizer costs and potential damage to your lawn.

Water Stress. Excessive Nitrogen causes higher evapotranspiration rates [the rate at which your lawn gives up its moisture to the air],This uses up the water in the roots' vicinity faster and means watering more frequently to keep the grass plants' moisture balance. It also restricts root development, so roots may not be able to reach available water.

Disease. Excessive Nitrogen accentuates the effects of disease and insect injury to grass plants.

Root Dieback. Too much Nitrogen can cause roots to dieback and decrease in size and number.

Reduced recovery from stress. Too much fertilizer exhausts the grassplants' carbohydrate reserves, restricting the turfs power to recuperate, and reducing its ability to endure heat, drought, cold, and winter desiccation.

How much fertilizer is too much? The Nitrogen level at which negative effects occur depends on the turfgrass species and cultivar, soil texture, amount and frequency of rain and irrigation, and whether grass clippings are removed or left on the turfgrass.As a rule-of-thumb, fertilization rates greater that 1 pound of actual Nitrogen per 1,000 sq. ft. per application exhaust grassplant carbohydrates.