Crabgrass Control

By Jeff Rugg

August 7, 2019 4 min read

Q: Our community replaced a bunch of sidewalks and curbs; then they repaired our lawns. They used grass seed instead of sod, and now we have a lot of crabgrass mixed in with the good lawn grass. How do we get rid of the crabgrass without hurting the new lawn grass?

A: Even though a lot of crabgrass sprouts in the spring, it can begin growing and continue developing all summer. The small plants are often unnoticed until they grow larger and begin producing seed stalks.

If the only weed you have is crabgrass, you are in luck. Crabgrass is an annual and will die when you get some freezing weather. Keep it mowed so it doesn't produce any seeds. You may have to do some hand-snipping if the seed stalks are below the mower height. There will still be crabgrass seeds in your soil, but pulling or cutting off as many as possible now will reduce the number of seeds that sprout next spring.

Next spring season, some of the remaining crabgrass seeds will sprout. Crabgrass seeds can sprout all summer long if the soil is bare and open to sunlight. Having a thick lawn will help prevent the crabgrass seeds from sprouting.

This fall, go ahead and add some more good grass seeds and do the typical follow-up care of watering, fertilizing, mowing and keeping tree leaves off. This will help fill in any of the bare spots that open up due to crabgrass dying during the fall. Fall is the best time to plant cool season grasses, and it is the time when the fewest weeds will germinate.

The other option for this fall is to sod the area yourself. If it is a small area, it won't cost that much, and you won't have a crabgrass problem. Even in southern states where you would plant the sod in the summer, you could still go ahead and do it now.

If you can get good coverage from the lawn by seeding this fall, you won't have to reseed next spring. Since you don't have to plant grass seed in the spring, you can use a pre-emergent weed killer to control crabgrass and other spring weeds. Almost all pre-emergent weed killers will prevent lawn grass seeds from growing, too, so you can't plant grass seed and use the pre-emergent weed killer at the same time.

Next spring, if you can't get the pre-emergent down before the crabgrass seeds emerge, there are a few products advertised to kill it. The sooner you notice the crabgrass and the smaller it is, the better these products will work. Look for products with an active ingredient called quinclorac. It is an excellent crabgrass killer that controls not only crabgrass but can also kill foxtail grass and some other weeds, such as clover and black medic.

Once the good grass is established, mow it at the high end of the proper height for the type of grass it is. The more shade the lawn covers the soil with the better. A taller lawn also has more leaves to produce food; thus, it will be healthier. More food also means more roots to spread into open spaces and gather more water when the weather dries out.

Anyone with grassy weeds in their lawn at this time of year will benefit from planting new grass seed this fall. Over the winter, watch to see what the grassy weed does. If it dies, it is an annual; using pre-emergent weed killers in the spring will dramatically help. If it doesn't die over the winter, it is a perennial that will need to be killed with an herbicide or dug up by hand.

Email questions to Jeff Rugg at [email protected] To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at

Photo credit: Counselling at Pixabay

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