If you had crabgrass last year, you have thousands of seeds in your lawn just waiting to sprout. And once that happens, you’ll likely be looking at crabgrass again all summer.
All it takes is one itty-bitty crabgrass seed to create a monster like this one.
Spring is the time to apply crabgrass preventer (aka preemergence treatment) to your lawn. It works by preventing seeds from germinating. You have a very short window of time to apply the preventer. Miss it and you’re stuck with another year of a crabgrass-choked yard. Here’s why.
Seed germination is triggered by soil heat. That’s why you’ll find crabgrass sprouting first near sidewalks, driveways or any other warm surface that heats up the soil nearby. Crabgrass usually sprouts after your lawn greens up in the spring. Applying crabgrass preventer too early is a mistake—it might lose its effectiveness before the seeds come to life. So you should apply preventer between your second and third mowings. The first treatment is by far the most important, but you’ll have other Johnny-come-lately seeds that hadn’t woken up yet and won’t be affected by the preventer. That’s especially true for seeds that are in cooler soil. That’s why you should apply a second treatment a few weeks later. Once you do that, you’ll have very little crabgrass the rest of the year.
Applying crabgrass preventer is as easy as filling your spreader and taking a stroll around your yard. If you’re worried about getting preventer in flower or vegetable seed beds, use a drop spreader rather than a broadcast spreader. Broadcast spreaders like the one shown spew material over a wide area rather than dropping it directly below the spreader.
Application is as simple as filling your broadcast spreader with crabgrass preventer and pushing it around your yard, just as you would with granular fertilizer. But beware. Preventer stops ALL seeds from germinating. If you get it on your vegetable or flower garden where you intend to plant seeds, nothing will grow! And don’t plant grass seed within eight weeks of applying crabgrass preventer, or the grass seed won’t germinate either.
You’ll have to apply the crabgrass preventer again next spring. You’ll still have dormant crabgrass seeds in your lawn raring to go—they can stay viable for years.
— Travis Larson, Senior Editor