Autumn turf tips

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

The deluge of rain the state received last week has certainly revived turfgrass that had been struggling from dry conditions the previous six weeks. Now the challenge is catching up with the flush of growth the rain has produced. Go slow on mowing if you haven’t been able to cut since last weekend as it is likely the turf has elongated several inches in just the past five days. If you have room to raise the height of cut this might be the time as it will make it easier to mow through the abundant growth.

Fall fertilization

The benefits of any Labor Day fertilizer applications are certainly being felt now, but if you haven’t applied a fertilizer and are still interested in giving the turfgrass a boost, fall is definitely a great time to fertilize. A fertilizer application in the fall will allow the turf to recover from any summer maladies and will help the turfgrass store carbohydrates that will be used next spring to initiate growth.

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 now 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 abundant rain ensures the turfgrass and weeds are actively growing right now, which is important to ensure the herbicides will be taken up and transported within the weeds. 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

If you’re going to reseed an area,now is the time to get going. We are probably past the ideal seeding window, but if you can still get seed out in the next week it will probably have enough time to establish before winter, at least as long as winter isn’t really early this year. 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 huge 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.

Core aeration

Another fall turf activity is core aeration. Golf courses throughout the state have been and are still punching holes in fairways and greens. Core aeration improves soil aeration (oxygen which roots need to grow), relieves compaction, and removes organic matter. Some will even follow core aeration with overseeding to spruce-up some thin areas. Any homeowners considering core aeration should make sure that all underground wires, such as shallowly buried invisible doggy fence wire, irrigation pipes, and sprinkler heads are well marked to avoid any unforeseen disasters.

Mulching leaves

If you look closely you can already see some leaves changing which means we’ll soon see leaves falling. 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, don’t “rev” the throttle to the high jackrabbit setting and blaze around the yard. 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 three to four 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 one half inch. This will help you clean-up any left over 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.

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