One of our most frequently asked spring lawn care questions involves tips for getting rid of crabgrass. Very quickly a small patch of crabgrass can overrun your yard and spread to flower beds and gardens. Crabgrass is one of the most difficult weeds to root out because it spreads so quickly. Prevention is always easier than getting rid of a problem and crabgrass is no different. The best time to prevent crabgrass is early to mid-April before seeds germinate and seedlings take root.
Know thine enemy. Crabgrass crawls from a central shallow root low across the ground. Before a crabgrass weed dies in the fall, it will have distributed thousands of seeds that will germinate the following spring. Crabgrass loves heat and dry weather and is especially attracted to areas that absorb a lot of heat such as alongside pathways, asphalt and pavement, and south-facing bare patches in your lawn. Crabgrass (smooth or large) is often confused with quack grass. Preemergent herbicides will not work on quack grass.
Crabgrass is a prolific seed producer and will distribute seeds across your lawn (and onto your neighbour’s) all summer long. If you or your neighbour had crabgrass last year, expect it will pop up in your lawn this year at an alarming rate. With Ontario’s ban in 2009 on many varieties of cosmetic pesticides and herbicides, combatting crabgrass got a little more difficult.
One safe alternative approved by the City of Ottawa is corn gluten meal. This corn by-product works by preventing new seeds from germinating (preemerging) and should be applied for crabgrass control in mid-April. Most preemergent herbicides work best when soil temperatures reach 10⁰C (50⁰F). You can buy a soil thermometer at your local garden centre. Another tried and true method is to watch for Forsythia blooms, once you see the yellow flowers you know the soil temperature is right. Preemergent herbicides can be applied later in the year to prevent new seeds from germinating, but will have no effect on seedlings and existing plants (which is why it’s safe for your lawn). The downside to a preemergent herbicide is that it indiscriminately prevents seed germination including grass seed.
Nutri Lawn also offers a post-emergent crabgrass control service.
Summer Crabgrass Treatments
You can root out crabgrass by hand if you’ve got some free time (though we’d love to explain the many options we can provide and save you the work). The roots will be easier to remove after a good rain. But the best defense against crabgrass is a thick healthy lawn. Thick lawns crowd out weeds. Encourage deep roots in your lawn with proper watering techniques, and don’t cut your grass too short. Keeping your mower on the highest one or two settings will help your grass shade the soil and prevent weeds from taking root.
The lawn care pros at Nutri Lawn Ottawa are ready to help you grow a thick and healthy lawn as well as tackle all of your lawn care challenges. Let us help you create a lawn that will be the envy of your neighbourhood and you can enjoy your property all summer long.