- Author: Karey Windbiel-Rojas
For best growth, most lawns need to be fertilized two to three times a year, at least once in fall and once in spring. Nitrogen is the only nutrient that turfgrass needs on a regular basis. However, it may be beneficial to apply a complete fertilizer containing nitrogen, phosphorus, and potassium at least once a year.
Many retail nurseries and garden centers carry both quick-release and slow-release fertilizers. Although more expensive, slow-release fertilizers have several advantages over quick-release products. They release nitrogen over a period of 8 to 10 or more weeks, thus feeding the lawn for a longer period and making it unlikely they'll burn the turf even if accidentally over-applied in some areas. They are also less likely to leach or run off with rain or irrigation.
Examples of slow-release products include sulfur-coated urea, urea formaldehyde, isobutylidene diurea (IBDU), and organic fertilizers such as composted manure. Quick-release products include ammonium nitrate, ammonium sulfate, calcium nitrate, and urea.
It is very important to apply the right amount of fertilizer, which varies according to turf species. Visit the UC IPM page on fertilizing lawns for help in determining the correct amount of fertilizer to apply. The site includes a calculator that allows you to customize your turf species and location to find out how much fertilizer to apply and when to apply it.
Be sure you have the correct type of spreader and that you know how to calibrate it properly. Drop spreaders are the best choice for assuring even fertilizer distribution.
As with all fertilizer and pesticide products (including weed killers), instructions on the label should be read, understood, and followed explicitly.
Modified slightly from the September 2012 issue of the Retail Nursery and Garden Center IPM News http://www.ipm.ucdavis.edu/RETAIL/retail-newsletter.html./span>