For Release March 27, 2005

Time to Think Crabby

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

April is just ahead and that means it's time to prevent crabgrass from being a pest in your yard! Crabgrass control is not nearly as difficult as it used to be, but you do have to follow through a step by step determination to see if you even need crabgrass control. Unlike dandelions or henbit, which you spray once you see, you need to control crabgrass before it starts. Once it starts growing it becomes tougher to control, and by the time many homeowners realize they have a problem, it's much too late to control.

So first of all take a look at your yard. Do you have thick tall grass where no open soil is showing? If so, then you are probably at a low risk for crabgrass. Do you know for a fact that you had a crabgrass problem last year? If you didn't see any strange grass show up late in the summer last year, then you probably don't have a lot of crabgrass seed laying around. Crabgrass seed doesn't blow in from a neighbor's yard. It is carried in on shoes, pets, lawn care equipment or with water. Once it's in the yard it can increase in a couple of years to be quite the pest.

If you have quite a few thin spots in your yard that you need to reseed this spring, then forget about applying crabgrass control. The crabgrass control products work by killing the seedlings as the seed starts to germinate. Unfortunately, they don't know the difference between crabgrass and fescue or bluegrass that you are trying to plant. So don't overseed and apply crabgrass preventer in the same season.

Crabgrass is an annual plant. It dies completely with the freezes of fall. This year's crabgrass will not come back from the roots of last year's crabgrass, it has to come from the seed. If you have thick matted grass with long runners that is starting to green up this spring, you don't have crabgrass, you probably have Bermudagrass. The crabgrass preventers won't do a thing for Bermudagrass control. Crabgrass seed can germinate just about all summer long. Even if it doesn't germinate until July, it can still go ahead and produce seed before frost. This is very critical to know depending on the type of herbicide that your crabgrass preventer contains.

You need to apply your crabgrass preventer within the next week or two, if you haven't already done so. The seed won't germinate until surface soil temperatures reach a consistent 55 to 60 degrees. The herbicide needs to be applied and activated with rain or irrigation ahead of the start of germination. Once the herbicide is applied, avoid disturbing the soil of your lawn. If you need to aerate or dethatch your yard, do this before applying your crabgrass preventer.

When you purchase your crabgrass preventer, read the label very carefully. Depending on the herbicide being used, you may need to apply a second treatment 6 to 9 weeks after the first. Some products are relatively short lived and failing to apply a second application will result in a late season crabgrass crop. Most products out there today will give you four to six months of control. For most yards this will be more than adequate.

If you also have broadleaf weeds blooming in your yard there are also products that contain crabgrass preventer AND broadleaf weed control. But remember that broadleaf weed control products by themselves will not control crabgrass and crabgrass control products by themselves will not control actively growing broadleaf weeds. Match the product to your need and get busy in the lawn, because spring is here!

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