When Should You Fertilize a Lawn in the Fall?

The grass may be greener on the other side of the fence, but your neighbors aren't using any special lawn care strategy to get it that way. Fertilizing your lawn isn't rocket science; many grasses only require fertilizing in the spring and the fall. The key is in timing.

Several factors determine when you should fertilize your grass. The three main ones are climate, your grass type and the fertilizer you're using. Additional factors may include whether you mulch your grass back into your lawn and the condition of your soil.

The U.S. Department of Agriculture divides the United States into plant hardiness zones. The optimal time for fall lawn fertilization differs from zone to zone. Check with your local cooperative extension office to find out what your hardiness zone is, and what that means for fertilizing your lawn.

Your lawn may have either warm-climate grass or cool-climate grass. Cool-climate grasses such as Bermuda grass thrive in the northern states; warm-climate grasses such as buffalo grass do well in the southern states. Each grass has its own growing season. You should apply fertilizer when the grass is actively growing, so your fall fertilization time will depend on when the grass goes dormant.

The type of fertilizer you use will depend on the condition of your soil. A good fertilizer should provide nutrients that the grass doesn't already get from the soil. A soil test can tell you the nutrient composition of the soil and thus suggest the type of fertilizer to use. Certain practices, such as mulching grass clippings back into the soil, will also affect the soil's nutrients. You can have your soil tested by the local extension office. Since certain fertilizers should not be used after your lawn has gone dormant, you should test early to determine the best fertilizer and the latest time that you can apply it to your lawn.