Crabgrass is an intrusive, fast growing, hard to control weed.
Once spring comes and the weather starts warming up, soil temperatures rise which causes crabgrass seeds to “wake up”. Early spring is the best time to put a pre-emergent crabgrass application down. Crabgrass preventer is effective for approximately two to three months. However, weather conditions and disturbance of the barrier (such frequent foot traffic or animals) may shorten its efficacy.
If you begin to see crabgrass plants in your yard, it is beneficial to rake before mowing. Raking disturbs the crabgrass from its natural position (like running a comb through your hair the wrong way). Use the rake to “fluff up” the crabgrass plant so the seed branches of the plant are more accessible to the mower (do not decrease the height setting on your mower). It may be tempting to skip this step, but doing this can get rid of as many as 2-3 times as many seed heads than if you didn’t rake.
It is a common myth that mowing your crabgrass down will kill it, but it will not kill it or even hinder its growth. It will actually make it harder to get rid of because it will start to grow flat and wide, rather than upright and tall. Crabgrass, unlike other plants, keeps generating seeds until winter comes, or until it is killed. Each crabgrass plant can produce over 150,000 seeds per year. Crabgrass seeds have a long germination cycle. The seeds that fall this year will not actually grow into plants until next year. It is important to realize and understand that the longer you wait to take care of crabgrass, the worse your problem will be the next year.
As crabgrass is next to impossible to control during the hot summer months without damaging your lawn, crabgrass problems should be addressed in the fall as well as the spring.
All crabgrass should be removed from the premises throughout the season. It is generally recommended to recycle your grass clippings. The exception to this is if you have crabgrass. You should dispose of any clippings that have crabgrass and completely remove them from your property. Recycling grass clippings with crabgrass will disperse the crabgrass seeds throughout your yard. It is also important to get rid of any crabgrass plants after they die. Crabgrass plants create a dense mat as they grow. After the plants are killed, that mat will continue to take up space and smother nearby grass. Crabgrass is an allelopathic plant. This means that it emits a toxin that hinders the growth of nearby plants.
Remember, the most effecive way to control crabgrass is prevention!