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Larry A. Sagers Regional Horticultural Specialist Utah State University Extension Service Thanksgiving Point Office © All Rights Reserved
I hear I need to fertilize or winterize my lawn in the fall. This seems to be an excuse to sell more fertilizer. Why should I apply fertilizer when the lawn is not growing?
Autumn is a misunderstood and often neglected time for turfgrass maintenance. The long hot summer takes its toll on the grass and the care given to the turf in the fall is most important. That care greatly affects the quality of the turfgrass the following year.
Maintenance operations in the fall are similar to those needed in the spring. The correct timing of those operations maintains an excellent fall appearance, a healthy winter turf, and a strong, balanced, early spring growth.
The food reserves that carry the turf through periods of hot weather the following summer are stored in the plant in the fall. As days become shorter and temperature moderate, grasses manufacture excess carbohydrates, to sustain themselves and to store for future needs. This process continues as long as the leaves remain green.
Fall is the only time turfgrass plants actually increase in weight. During the spring and summer, growth burns more stored energy than the plant manufactures. Spring and summer fertilization affect the color and growth rate of the turf, but do little to build carbohydrate reserves.
Fall fertilization is important. Applying nitrogen fertilizer late in the season has several advantages. It improves the fall and the winter color and enhances greening in the spring without stimulating excessive shoot growth. It increases shoot density as well as fall, winter, and spring root growth.
Fall fertilization reduces some disease problems. Soft, succulent shoot growth in the spring is very susceptible to disease.
Soil testing is the only accurate way to determine what formulation of fertilizer is need for turfgrass. Avoid applying excessive nutrients that have no value to the turf or are already available in the soil.
All turfgrass need high nitrogen to keep it growing well. Add other nutrients when soil testing show a need to do so.