Crabgrass gets its name because it grows low to the ground with stems that radiate out from the center of the grass clump, resembling crab legs. Seeds begin to sprout in mid-spring, as soon as the soil temperature reaches 55 °F, and crabgrass can quickly become a problem during the summer because it is able to grow vigorously in hot, dry conditions. Crabgrass is an opportunistic annual weed that will grow in the thin and bare spots in your lawn. Before it dies in the fall, a single crabgrass plant produces thousands of seeds that can germinate the following spring.
How to Kill Crabgrass
If you only have a few crabgrass plants in your lawn, you can treat them with a ready-to-use product like Scotts® Spot Weed Control - For Lawns. This spray kills listed weeds, including crabgrass, down to the root without harming your lawn, when used as directed. You can also pull crabgrass by hand using a hand trowel or digging knife, but it should be done early in the season before the plants can produce seeds.
How to Prevent Crabgrass in the Spring
It is far easier to stop crabgrass in the spring before it becomes a nuisance in the summer. Crabgrass seeds can start to germinate in the spring once the soil reaches 55 °F, so crabgrass preventers, like
Scotts® Turf Builder® Halts® Crabgrass Preventer with Lawn Food, should be applied in early to mid-spring before the crabgrass starts to develop. If you’re also dealing with broadleaf weeds, use Scotts® Turf Builder® Triple Action instead. Not only does it prevent crabgrass (plus other grassy weeds) for 4 months and feed your lawn, but it also kills weeds like dandelion and clover. Just seeded (or reseeded) your lawn? Opt for Scotts® Turf Builder® Triple Action Built For Seeding
instead. It protects new grass from crabgrass and other weeds while helping it get established more quickly and grow thicker. (Most other crabgrass preventers stop both grass and crabgrass seed from growing.)
Here are a few more tips for preventing crabgrass:
Mow at the proper height.
You can discourage crabgrass by mowing at the proper height for your grass type. Mowing higher, usually at one of the top two setting on your mower, allows taller grass blades to shade the soil, which in turn helps prevent the germination of crabgrass seeds.
A thick, full lawn seldom contains much crabgrass. When your lawn is underfed and stressed out, however, it has a greater chance of being taken over by weeds. Feeding your lawn regularly, every 6 to 8 weeks, during the growing season with a lawn fertilizer like Scotts® Turf Builder® Lawn Food (as directed) helps your lawn stay thick and lush, making it less welcoming to weeds (like crabgrass) by leaving little space for them to grow.
Deep water your lawn.
Weeds are better adapted to adverse growing conditions than most lawn grasses. Shallow, frequent watering encourages shallow root growth, making the grass more likely to suffer during periods of heat and drought. That kind of stress can lead to thin patches and bare spots that crabgrass will take advantage of. Instead, water lawns deeply (to a depth of 6 to 8 inches) and infrequently to encourage your lawn to develop deeper roots, so it can grow thicker to help crowd out weeds.
Repair lawn damage.
Crabgrass plants will be killed by frost in the fall, leaving behind bare spots. Don’t panic! All you need to do is repair the bare spots to help keep new weeds out. Fill the spots with a patching product, like Scotts® EZ Seed® Patch & Repair, and keep it watered until the new grass is established.