Crabgrass is one of the most difficult weeds to eradicate from your lawn. With the 2009 ban in Ontario on cosmetic herbicides and pesticides, organic weed killer options were explored. The problem with crabgrass is that very quickly a small patch can take over your lawn, flower beds, and gardens. Because crabgrass spreads so quickly, prevention is the easiest way to get rid of this weed, and the best time to prevent crabgrass is early to mid-April before seeds germinate and seedlings take root.
Crabgrass spreads from a central shallow root low across the ground. Before crabgrass weeds die in the fall, it will have dispersed thousands of seeds that will germinate the following spring. Crabgrass prefers heat and dryer weather and is especially prone to areas that absorb a lot of heat such as alongside asphalt and pavement, pathways and south-facing bare patches in your lawn. Crabgrass (smooth or large) is often mistaken for quack grass. Preemergent herbicides are not effective on quack grass.
A preemergent herbicide prevents seeds from germinating but has no effect on plants and seedlings. Typically a preemergent herbicide is good for about 50 days, and at that point dormant crabgrass seeds may take root so a reapplication may be advised, particularly around sidewalks, pathways, and driveways.
Chemical based herbicides are banned, but corn gluten meal is an organic weed killer (a preemergent herbicide) and is a corn by-product. Crabgrass is prolific. If you had crabgrass last year, if your neighbour had crabgrass last year, you can expect it to pop up again and in some new places too. Crabgrass begins to germinate when the soil reaches 10⁰C (50⁰F) – usually mid-April. You can purchase an inexpensive soil thermometer or watch for the Forsythia to bloom. The yellow flowers emerging will tattle on the soil temperature pretty reliably.
The downside to a corn gluten meal is that it’s indiscriminate. It will prevent all seeds from germinating, so if you want to prevent crabgrass you would be well-advised to wait to overseed your lawn.
Nutri Lawn also offers a post-emergent crabgrass control service.
Summer Crabgrass Treatments
If you’ve got the time and inclination you can pull crabgrass by hand (though we’d love to explain the many options we can provide and save you the work). Weeding is always easier after a good rain when the soil is moist. The best way to prevent crabgrass, or any other weed, is to have a thick healthy lawn. Thick lawns need deep roots and you can encourage that will proper watering techniques. Keep your lawn mower one of the top two height settings. Cutting your grass too short leaves the soil open to the sun and crabgrass seeds will germinate more quickly.
The lawn care experts at Nutri Lawn Burlington are ready to help your lawn grow thick and healthy, and we can tackle all of your lawn care headaches. Let us help you create a lawn you will be proud of and will enjoy all summer long!