Fall 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.
After a summer of rain and cool temperatures, September has had some of the driest and warmest weather we’ve had all year. If the turf hasn’t been irrigated, its growth has certainly slowed, and it’s unlikely you’ve seen any great response from a fertilizer application in late August or early September. If you didn’t apply any fertilizer in early September and are looking to boost the turf as the fall moves along, I would probably wait until some moisture returns before applying any fertilizer.
Rust and red thread
Both rust and red thread have been showing up in lawns recently. If your lawn appears yellowish or orange-ish from a distance and upon closer inspection of leaf blades reveals yellow to dark brown spores, you’ve got rust. The good news is that in all but the most severe cases simply keeping up on your mowing and applying fertilizer should stimulate the turf to outgrow the rust. However, therein lies the challenge that moisture has been lacking and the turf growth has really slowed in the last couple weeks, unless you’ve been irrigating.
Red thread is a pesky disease that we have been receiving reports on from homeowners.
Red thread, if a problem, is usually found in under fertilized/slightly starved turf. With the relatively good growing weather that we’ve experienced throughout much of the year, many of the fertilizer applications that were applied earlier in the season have probably run out and now the turf could probably use another fertilizer application. Red thread is often found in areas dominated by fine fescues or perennial ryegrass. Red thread is easily identified by the pinkish-red mycelium that is threadlike and surrounds the leaf blade. In some extreme cases, it might remind you of miniature balls of pink cotton candy. The areas infected by red thread will die and the turf may appear wilted. The simplest fix for red thread is to apply a quick release nitrogen carrier such as urea at about 0.5 lb. N/1000 ft.2 to encourage turf growth to mask the symptoms, but once again we need moisture or irrigation for a fertilizer application to be effective.
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. Hopefully, we’ll have some precipitation in the next couple weeks to ensure the weeds are actively growing, otherwise if it remains dry the effectiveness of these applications may be reduced. 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.
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.
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.
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 a 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.
We recently revamped our MSU turfgrass website. We now are adding regular blogs on turfgrass conditions throughout the state. So if you want to stay on top of the turf throughout the fall, check out our website.
Dr. Frank's work is funded in part by MSU's AgBioResearch.