Crabgrass, foxtail, and other annual grassy weeds that have escaped pre-emergent control, like Houdini from a straitjacket, can now be eliminated with a post-emergent herbicide. Control ugly summer weeds around the edges of sidewalks, driveways, and grass strips between the sidewalk and street curb where pre-emergence breaks down from the excessive heat. Don’t let those summer weeds put you in a straitjacket. Check out these tips for post-emergent control of summer weeds.

What is Crabgrass?

Crabgrass is an annual grassy weed. Of all lawn weeds, crabgrass is the most common and bothersome. Crabgrass is probably the only weed that everyone hates. Even though it is a grass, crabgrass doesn’t blend in with lawn grasses in color, habit, or texture and can be so aggressive that it out competes the good turf grass.

Crabgrass Annual Grass Weed

What Does Crabgrass Look Like?

Crabgrass is a low growing weed with lots of stems that form flat clumps. Clumps spread out and root along the stems at joints. The blades are coarse, pointed and short. As crabgrass matures, they send up branched seed heads that have thousands of crabgrass seeds. Looking out over your yard, crabgrass shows up as patches of much lighter green than the rest of your turf lawn.

How Does Crabgrass get into My Lawn?

Crabgrass germinates each spring from seed like other annual grass weeds, such as foxtail, barnyard, and goose grass. Low-growing and prostrate to the ground forcing out weak and summer-stressed turf grasses for prime real estate in your lawn. Annual grassy weeds form seed heads in late summer and then die at first frost, leaving dormant weed seeds and bare spots.

Uncle's Q-Bomb Post-Emergent Products

How Do I Kill Crabgrass?

Control crabgrass and other annual grassy weeds with one of Uncle’s Q-Bomb products. Q-Bomb, post-emergent crabgrass herbicides containing quinclorac, will control a wide variety of grass weeds and broadleaf weeds, including crabgrass, foxtail, clover, dandelion, black medic, English daisy, morning glory, dollarweed, speedwell, torpedo grass, barnyard grass, bindweed, signal grass, wild violet, and ground ivy. Use a broadcast or spot treatments to actively growing weeds as a post-emergence.

Do not broadcast apply these products when temperatures are above 90 degrees; temporary turfgrass discoloration can also be expected with spot treatments when air temperatures exceed 90 degrees.

Uncle’s tip: Always read and follow label directions before applying any pesticide.

Tips for Effective Post-Emergence Crabgrass Control

  • Uncle’s Q-Bomb products are most effective on crabgrass when applied to newly germinated crabgrass with one to six leaf while having no more than two tillers and after crabgrass has matured to five tillers or greater.
  • Do not mow 2 days before or after a Q-Bomb application. If soil is dry, irrigate turf grass in advance for best results. No rainfall or water for 24 hours after application. Apply ½ inch of water 2-7 days after application, if no rainfall has occurred during this time period.
  • Early summer treatments are generally more effective. Applications in mid-summer (July 15-August 15) to older, drought stressed grassy weeds are less effective. Late summer applications (after  August 15) to mature crabgrass can be very effective.

See Related: Summer Grassy Weed Identification

What Is the Best Way to Prevent Crabgrass?

The best way to eliminate crabgrass in your lawn is to apply a pre-emergent barrier in spring. Prevent crabgrass germination with the two-application formula of Loveland’s Prevent, a crabgrass preventer with fertilizer. The first application of Prevent goes down in early spring before crabgrass seeds can germinate, and the second application of Prevent will go down 10-12 weeks later.

More Related Articles to Crabgrass and Summer Weeds


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When to Apply to Prevent Crabgrass

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