Ideas for better living from Colorado State University
A few snow storms may separate us from our lawns between September and May, but this is still a good time to review those numbers on a bag of lawn fertilizer. What do they mean? "10-10-10," for example, means that the fertilizer contains ten percent nitrogen, ten percent phosphoric acid and ten percent potash. Or, you may see a bag with a "45-0-0." It contains urea, which is 45 percent nitrogen. This formulation contains no phosphoric acid or potash. As a rule, phosphorus is only rarely deficient. Potash is not really needed, except in some very sandy soils. Most bluegrass lawns will need about 4 pounds of nitrogen per 1,000 feet each growing season. It is best to add not more than 1 pound per 1,000 square feet at a time.
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010