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Crabgrass Post-Emergent

You may have missed using a pre-emergent crabgrass preventer or put it on too late this spring, but all hope is not lost.


Crabgrass is a warm-season annual grass that grows best in the middle of the summer when temperatures are hot. It is not shade tolerant so you will see it congregate along sidewalks or in cracks along the edge of the road or driveway. The plant winters over as seed and comes up in mid to late May. The plant itself is killed off by fall frost.

Crabgrass is much easier to prevent than kill, so it is always a good idea to use a pre-emergent in the spring. If the time to apply a pre-emergent has passed there are some ways to help prevent crabgrass from germinating. Use a mower height of 2.5 – 3 inches during the warmer months. This will increase shade on the surface and decrease the chance of crabgrass seeds from germinating. Keep a healthy lawn and fill in bare spots with grass seed. The less open soil there is, the less likely crabgrass seeds will germinate.

Weed Out with Q

In cases where these steps did not do the job, there is a wonderful product to eradicate the problem. The post-emergent crabgrass and broadleaf weed killer Weed Out with Q will kill crabgrass and dandelions, but won't hurt your lawn. Use only when daytime temperatures are under 90 degrees.