Fall is the most important time of the year to fertilize your lawn. Fertilizing only in the spring or the summer will deprive your lawn of the extended benefits of fall fertilization.
During the summer the grass plant produces energy from photosynthesis that it uses for top growth. As temperatures drop in the fall root growth is favored over plant growth. Energy that the plant produces in the fall is used for root growth. Excess energy is stored in the roots for future use. This storage of energy means better winter survival and earlier spring green up without the extra mowing that comes with spring fertilization.
Advantages of fall fertilization include stronger root growth, increased turf density, and increased storage of energy reserves by the grass plant. New root growth results in a healthier turf throughout the next growing season. Lawns that are fertilized late in the season are often deeper in color throughout the following summer.
Results from Research at Ohio State University have shown that turf fertilized in September and then again in October has better fall and winter color than turf that was not. In addition spring green up can occur two to six weeks earlier when the turf was fertilized the previous fall. Greater levels of stored energy were found in turf fertilized in the fall then turf only fertilized in the spring. The greater the levels of stored energy the greater the stress tolerance and ability of the plant to recover from traffic, insect and disease damage.
It is important to remember that fall fertilization must be done while the turf is still green. Fertilizer applied too late in the fall when the grass has turned brown will have no effect. To have a green and healthy lawn requires that we follow one of the basic fundamentals of lawn care; fertilize on a regular basis.
As a general rule, lawn fertilizer should be applied four times a year. An easy way to remember is to use the Holidays as a guideline. The Holidays to apply lawn fertilizer are: Easter, Memorial Day, Labor Day, and Halloween.
If you only fertilize your lawn twice a year, make one application in the spring and one in the fall. If you only fertilize once a year, make sure to do it in the fall.