MSU Extension

Fall fertilization

Many turf sites are in need of a fertilizer application. A multitude of stresses this summer have resulted in thinning turf that, if not filled in with turf, will fill in with weeds. Fertilizing in the fall will result in a moderate top-growth response and give the plant some extra energy to develop roots and fill in the voids. If you’re going to fertilize in the fall, I would go ahead and get the application down so the plant can benefit while the growing conditions are still favorable.

Fall broadleaf weed control

Fall is the ideal time to control broadleaf weeds because the weeds are storing carbohydrates in their root system and are more susceptible to herbicide applications. So if your turf has been overtaken by a bevy of broadleaf weeds, applying a herbicide in late September or early October will make a difference in what you battle next year. Apply the herbicides on a sunny day when rain is not in the forecast for 24 hours. We want the herbicides to dry on the leaf surfaces and not be immediately washed off. The recent rains that have covered most of the state should ensure weeds are actively growing and any herbicide applications should be very effective.

There are many different herbicides that could be used including the most common three-way broadleaf weed control mixtures. As with any pesticide application, always make sure to wear the appropriate safety attire and follow all label recommendations. The greatest shortcoming of killing broadleaf weeds at this time of year is that you really don’t get to watch them die. In many cases, you may not see the obliteration of these weeds this fall, but next year they won’t be there or you will have at least reduced their numbers.

Fall seeding

Now that it’s finally officially fall, many people may still think of reseeding some damaged areas in their turf. If you still want to do some seeding you definitely want to get going. We are probably past the ideal seeding window, but if we have a mild fall, seedings at this time can still be successful.

Along the Grand Rapids-Lansing-Detroit corridor, you are probably safe to seed until around October 1 and have enough time for the seed to germinate and survive the winter. If you’re north of that line and still want to seed, hope for a warm fall. Consider that seed is relatively inexpensive and if you’re not doing a large area, I wouldn’t worry too much. If it doesn’t survive the winter, you’ve got some practice in this fall and will be ready to go next spring.

Mulching leaves

Many trees have already started shedding leaves. Tree leaves are nature’s way of giving you some free fertilizer and organic matter for your turf. If you haven’t tried to mulch leaves back into the turf, maybe this is the year you start. Here’s what you need to know to successfully mow leaves into the turf. First of all, make sure your mower has a sharp blade; after a long season of mowing the blades may be dull at this time of year and trying to chop up leaves will be more challenging with a dull blade.

Second, raise the mower as high as it will go and mow at your normal speed. Try to mow the leaves when they are moist from the morning dew, but don’t mow them when they’re really wet. This will prevent the leaves from blowing all over the place and will help with your allergies. Finally, don’t let the leaves pile up too high before you mow; too high would probably be greater than 3 to 4 inches of leaf depth on the turf. Mulching leaves helps the turf by returning nutrients and organic matter, which can be especially beneficial on poor soils.

Final mowing

Many people ask about lowering the mowing height for the final mowing of the year. When you get past the leaf mulching period in the fall and the turf has essentially stopped its top-growth, it is OK to lower the mowing height to clean-up the turf and prevent the turf from being too tall going into winter. I would recommend that you lower the mowing height no more than one notch on your mower (typically half an inch). This will help you clean up any leftover leaf mulch or debris and give the turf a little trim before winter sets in.

Dr. Frank's work is funded in part by MSU's AgBioResearch.