So, Why Do I Have All This Crabgrass?

It is probably the most frequent call, and the most frequently asked question since June.  “Why do I have all this crabgrass in my yard?

“I got the treatment in March.  I paid good money for pre-emergent to prevent crabgrass from growing later in the summer.  And now I have crabgrass everywhere.  Why?”

We hear it at least once a day…from residential clients, school athletic departments, and people who did their own spring treatments.  Why is there so much crabgrass (Digitaria) this summer.

The answer is pretty simple if you think about it. A lot of people put down pre-emergent herbicide this spring, only to have it washed away by twice the amount of spring rains that we usually get.  Want some numbers?  On average the Miami Valley will get about 15 inches of rain between mid-March and mid-June.  This year that number ballooned to 28 inches of rain.  And all that rain either washed away the granular herbicide put down to prevent crabgrass…or diluted it to the point of being ineffective.

So what can you do now?

Well, there are post-emergent treatments like the herbicide Tenacity;  but those treatments are expensive, they turn crabgrass an ugly white color on its way to extinction, and it usually takes two to three treatments to wipe it out.  By the time it’s gone it’s fall and last year’s problem.

The other thing you can do is mow more frequently to make sure crabgrass doesn’t go to seed.  Unlike bluegrass, crabgrass is an ‘annual’ plant without a rhizome root system, so the only way it comes back the following year is by seed.  Keep the tops cut off to ensure that it doesn’t.

Last, if you’re cancelling summer lawn treatments because you don’t feel the need, understand that by growing a thicker lawn of more desirable grasses (like bluegrass) you make it tougher for crabgrass to get a foothold.  So understand, the more you feed your lawn from April through August the less chance you have to having crabgrass.

In a nutshell, this is why there’s so much crabgrass thus summer.  And if it makes you feel better, the problem is just not with your lawn.  A lot of people have it.  Next year you do what you can do…and hope Mother Nature cooperates.