Warm-Season Grass: 6 Tips for Fall Lawn Care

October 7, 2020


Warm-Season Grass: 6 Tips for Fall Lawn Care

Fall has arrived. Temperatures and leaves are dropping, and the long days and sweltering heat of summer are a thing of the past. As the season changes, the differences in cool-season and warm-season turfgrass varieties couldn’t be more pronounced. Cool-season grasses that have been dormant during the summer heat are beginning to green up and come back to life. Meanwhile, warm-season grasses that have been flourishing in the summer weather are preparing to hunker down for winter. So it’s no surprise that fall care for a warm-season and a cool-season lawn is very different. Today, we’re going to talk about fall lawn care for warm-season grass varieties with these six outstanding tips.

Warm-Season Grass - 6 Tips for Fall Lawn Care [infographic]

1. Test Your Soil

It’s always good to know what your soil is up to, but many homeowners have never even heard of soil testing. But without soil testing, fertilizing is just guesswork. And beyond fertilizing, the information gathered from a soil test allows you to amend the soil to correct pH and other issues.

Some garden stores sell soil testing kits. However, for more accurate and more insightful test results, you can bring your soil sample to your local extension office. The results are usually available within a few days and often include recommendations for corrective actions. Expect recommendations on the type and amount of fertilizer you’ll need, as well as other ways you can improve your soil.

Testing and correcting your soil now, in the fall, gives your lawn the best chance to green up beautifully in the spring. It makes sense to have ideal soil conditions before your turf starts to come out of dormancy in early spring. It is easier to make changes to your soil in fall than in winter, so now is the perfect time to test and improve your soil.

2. Fertilize, But Not Too Late

The best time to fertilize your warm-season turfgrass in the fall is six to eight weeks before the first frost of the season. For Bermudagrass, you can fertilize even four or five weeks before the frost. But don’t wait, because fertilizing too late is actually harmful.

It’s always a good idea to fertilize your lawn at least twice a year, once in the spring and once in the fall. But it’s also important to keep in mind what a fresh dose of fertilizer does to the grass plant. Nitrogen is a critical component of chlorophyll, and chlorophyll enables photosynthesis. With a burst in photosynthesis, plants can produce and store sugars that will feed the dormant grass through the winter and in the early stages of the spring green-up. But if you fertilize too late, the nitrogen infusion can interfere with your turf’s natural process of going dormant. Dormancy protects the grass during the winter. Keeping it from going dormant before the weather changes can actually damage the plant.

3. Don’t Get Overzealous With Dethatching and Aerating

There’s a lot of mixed messaging around dethatching and aerating. Supposedly, both are necessary to open up your soil and get water and nutrients to your turfgrass roots. But we want to shed a little light on that.

Yes, aerating is very helpful, though it is not always necessary for every single lawn. Aerating helps open up and loosen your soil. If your soil is compacted or clayey, it can be hard for fertilizer, water, and nutrients to reach the roots. So it makes sense to aerate, especially right before fertilizing. But if you think about it, ripping up chunks of dirt—and grass with it—is not exactly a cakewalk for your lawn. Aerating is good for your lawn, but it is also stressful. And fall, just before your grass goes dormant, is not the time to stress it out.

The same is true of dethatching. Dethatching can be helpful if your thatch has gotten thicker than about a half-inch. But it can rip up your lawn, and that’s not what you want to do just before winter settles in. Give your turf a break and let it store up its reserves as it prepared to go dormant for the winter.

4. Stop Watering, But Not Too Soon

As long as your grass is still growing, it needs water. Typically, turf needs about one inch of water a week. If you get an inch of rain, that’s sufficient. If not, go ahead and water your lawn. But keep an eye on your turf. Once it starts to go dormant, stop watering. It’s not growing, and the water from natural precipitation should be enough to keep it over the winter. Irrigating a dormant lawn will leave your grass soaked and soggy, which can lead to fungi, weeds, and disease.

5. Now Is a Great Time to Treat Weeds

As your grass turns brown and goes dormant, you have the perfect opportunity to hit some hardy, cool-season weeds. For one thing, a brown lawn makes it easy to see those bright green weeds, which will stick out like a sore thumb. Secondly, when your lawn is dormant, there is less worry about accidentally damaging your grass. It’s still a good idea to avoid spraying your dormant turf with herbicide. But even if you accidentally kill off a little turf, it won’t show up that way it would in the summer, and your turf will have a chance to fill back in during the spring green-up.

Go after weeds with a post-emergent herbicide. It’s best to use a selective herbicide to avoid damaging your turf and other plants in your yard. Some herbicides work best on specific weeds, and you may need more than one type of treatment. You can always take some pictures of your weeds and bring them to your local garden store. If the associates know what they’re doing, they should be able to point you to the right herbicide for your lawn.

6. Don’t Let Leaves Pile Up

As the leaves fall, they can pile up and suffocate your lawn. A blanket of fallen leaves is never good for your turf. The leaves can hold moisture, which can encourage fungus growth and other diseases. If the leaves get matted down, such as when it rains, they could smother your dormant grass.

If the leaves start to fall while your turf is still growing, you can mow over them and chop them up into a healthy mulch to feed your lawn. It may take a couple of passes with the mower to get the leaves small enough. The mulched leaves should be in pieces no larger than a dime.

Once your lawn is dormant, the best course of action is to rake the leaves into a pile where there is no grass. There’s no point in feeding a dormant lawn. There are plenty of things to do with the pile of leaves, but one of the best options is to use it as part of a DIY compost heap. A compost heap needs different kinds of organic materials, and mixing in some dry leaves is one part of the process.

Don’t Slouch on Fall Lawn Care

Remember that fall is still a time to keep working on your lawn. Once the weather gets cold enough for regular frosts, and your lawn has gone dormant, you can take a step back—though there is still some work to be done. But that won’t be for a while. So don’t neglect fall lawn care. Putting in the work now will pay off in a lush, vibrant green-up in the spring.

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