Good news! Barring any sudden, severe drought at this late point in the summer, preparing your lawn for fall will be a bit easier than it would in a normal year.
We’ve had no dry spell this summer. Consequently, the grass didn’t go dormant, brown up, crunch under foot and create good conditions for weeds to take up residence. This means that we shouldn’t have to cross our fingers and hope that our lawns will green up with the return of cooler temperatures and regular rainfall.
This fall, your major lawn care tasks will be to renovate any bare spots caused by grubs – after treating for them of course – and applying weed control to broadleaf weeds before they go to seed. This will reduce the chance of seeds germinating first thing in spring.
Grass will continue to grow and make food through photosynthesis until the ground freezes. The turfgrass plants are trying to store as much food in their roots as possible before going dormant so they have sufficient energy to break dormancy in the spring. To be successful, your lawn needs that important inch of water a week and soil nutrients. Although nature usually cooperates in the fall by providing enough rain, you should be prepared to water if nature doesn’t come through.
Fertilizing in the fall replenishes the soil nutrients that the grass plants used during the summer. Lack of summer dormancy means that your turfgrass extracted more minerals and nutrients from the soil to support its ongoing photosynthesis. These nutrients need to be replenished to assure that the grass plants will be able to manufacture sufficient food to sustain themselves through the winter and into early spring.
Remember, fertilizer is not plant food. Plants make their own food through photosynthesis. For that reaction to take place, however, the plants need minerals and nutrients present in the soil. If your soil is deficient in any of these nutrients, they need to be replenished through fertilization. You could look at fertilizer as vitamin supplements for plants.
With the definition of fertilization in mind, I feel safe in writing that not all lawns need fertilization. If all the essential nutrients are present in your soil, replenishing them is like taking excess vitamin supplements. It doesn’t do any good and may do harm. A good rule of thumb is that, if you needed to fertilize in the spring, you need to fertilize in the fall. If you use a granular fertilizer, you either have to time the application right before it rains or be prepared to water it into the soil.
Fall is a good season to aerate your lawn, especially if the grass is thick and the soil heavy, as in clay. Aerating takes many forms. The urban legend that you only have to mow the lawn wearing golf shoes is just that – an urban legend. Aerification is done to loosen the soil. The holes have to penetrate deeper than the roots, and an actual soil plug has to be removed to give the remaining soil space in which to expand.
Perhaps the most difficult task is anticipating when your last mowing will be so you can drop your mower down to two or two-and-a-half inches for that final cut of the season. Overwintering with a crew cut will reduce your lawn’s susceptibility to winter fungal diseases. The lawn will also look better when the snow melts next spring because it won’t have that matted look.