Late Fall Lawncare

The fall is a great time to improve our lawns. We have now passed the correct timing for overseeding lawns, but there are other improvements we can still make. Controlling perennial broadleaf weeds and winter annual weeds can be done in October and fertilizers may be applied if necessary.

Broadleaf weeds

perennial lawn weed collage
Perennial Broadleaf Weeds

Perennial broadleaf weeds including dandelions, creeping Charlie or ground ivy, and clover are best controlled in the fall once the weeds have begun their preparations for winter. In the fall, these perennial weeds will move sugars that they use for energy from the above ground portions of the plant down into the roots to store them for next spring. If they are sprayed during this phase of their lifecycle, they are more likely to take that herbicide down into the roots to be more effective than if done in the spring. Spray these weeds with a 2,4-D product 2 or 3 times from late September through the end of October. Wait to spray after temperatures consistently drop to below 80 degrees so the herbicide doesn’t volatilize in hot, humid weather.

Weedy grasses

2018-04-20 12.52.00
Henbit in bloom in the spring

The fall is not the time to worry about or treat for summer annual weeds such as crabgrass. Those plants that are still alive will die with the first frost and the seed will not germinate until next spring when the weather warms back up again. However, you can treat now for winter annual weeds such as henbit and speedwell. Once they have germinated this fall you can use a 2,4-D product, which can be applied as a late October application both for the winter annual weeds and for perennial broadleaf weeds.

Using pesticides correctly

Remember, when using pesticides always be careful and apply pesticides according to the label. Any material used to maintain a landscape, including fertilizer, sand, or pesticides, can end up in the storm sewer and lead to pollution of lakes, rivers, and streams. In the same manner, even our grass clippings and leaves can pollute our water supply. There are ways to manage our landscapes while reducing water pollution.

The following will help when managing our lawns this fall:

  1. Any fertilizers, pesticides, and grass clippings should be swept back onto the landscape. Using a leaf blower will work as well. The idea is to keep these items on plant material rather than on the hardscape that leads easily to the storm sewer.
  2. Raking up leaves in the fall will also help reduce the amount of leaf debris that ends up in water.
  3. Check your sprayers before using to ensure they are properly calibrated and the nozzles are not clogged.
  4. Thatch layers in the lawn can become a natural barrier to prevent infiltration. Aerate the lawn to reduce the thatch layer to allow lawn products to infiltrate their intended areas.

Fertilizer

As for fertilizer applications, the fall fertilization is the most important fertilizer application for a lawn. However, fall fertilization recommendations have changed over the past couple of years. For a lawn, a Labor Day to mid-September application of slow release fertilizer is still recommended. Apply a granule with 50% slow release nitrogen or less. If additional nitrogen fertilizer is required later in the fall, use a product with a quick release nitrogen in mid-October. We used to recommend Halloween or later for the second fertilizer application and we thought two applications were necessary. New research is showing us that a second application of nitrogen fertilizer may not even be necessary, but if it is, we should move the timing up to more like Columbus Day rather than the typical Halloween time frame. This information is from Bill Kreuser, Assistant Professor and Turfgrass Extension Specialist from the University of Nebraska-Lincoln.

Fall Lawncare

fall landscapeAs we draw closer to fall, we can start to prepare our lawns for winter. I wanted to take time, this week, to cover all of those items on your fall lawncare “to do” list.

It is now time to reseed your lawns for the fall. This is best done in the late summer or early fall, anytime between August 15 and September 15 of the year. The rule of thumb is that that for each week grasses are seeded before Labor Day, maturation is speeded by two weeks. If you reseed after September 15 you will probably have some success, but not as much. The seed that you put out on the ground may sprout and some might even overwinter, but much of it may die from winterkill because the root systems will not be fully developed. If you are a homeowner who wants to sod an area of your lawn, you can do that until they can no longer cut it from the fields. Do remember to keep newly seeded or sodded areas watered throughout the fall and in the spring.

Bare lawn in need of overseeding.
Bare lawn in need of overseeding.

Good turfgrass choices for Southeast Nebraska include Turf-type tall fescue or Kentucky Bluegrass.   Using seed that is 100 percent of either of these or a mix of the two types would be great choices for Nebraska. You can buy mixes of turfgrass seed, but avoid mixes that contain annual ryegrass, ‘Linn’ perennial ryegrass, or ‘Kenblue’ Kentucky Bluegrass. Make sure that the grass you buy contains less than 0.3 percent weed seed and no noxious weed seeds. We can also use Buffalograss in our lawns for a warm season grass, but warm season grasses should be plugged in June and July.

As for fertilizer applications, the fall fertilization is the most important fertilizer application for a lawn. Two applications in the fall are recommended for Kentucky bluegrass and only one is recommended for tall fescue, but one application for either species is better than none. The timing for fall fertilizer applications is Labor Day and Halloween if you do two applications and Halloween if you do only one application.

The fall is the best time to control broadleaf perennial weeds such as dandelion and clover. You can add a broadleaf herbicide to your lawn fertilizer to get a two-for-one application. It is often sold in stores as a combined product. The best herbicide choices for homeowners would be anything that contains 2,4-D or a triclopyr product for clover and ground ivy or creeping Charlie.

Photo by Nic Colgrove
Photo by Nic Colgrove

If you need to aerate your lawns, now is a good time to do that. You can still aerate your lawns into November if you don’t get around to it until then. Aeration is best done in the spring or the fall of the year, but it is not necessary to do it every year, if you don’t want to. Aeration is done to break up a heavy thatch layer in the grass and to reduce the compaction of the soil. The thatch layer is the layer of dead organic matter in between the grass blades and the soil line. Leaving the clippings on the lawn does not increase the thatch layer, in fact it can actually give you enough nitrogen to replace one fertilizer treatment for the year. If your thatch layer is more than one half of an inch, you may want to aerate your lawn, if it is less than that, you may decide that it is not necessary to aerate this year.