Anyone who has a lawn in Minnesota knows what crabgrass is, but not everyone knows how to prevent crabgrass from growing or how to treat it once it is actively growing in your lawn during the heat of summer. An ounce of prevention is worth a pound of cure.

Crabgrass

Biology:

Crabgrass is a warm-season annual that grows best in the middle of summer when the temperatures are hot. It is not shade tolerant so you will see it congregate along sidewalks or in cracks, on the edge of the lawn, by the road or your driveway, any sunny bare spot in your lawn. A single crabgrass plant will produce thousands of seeds that can germinate the following spring. The plant is killed off by fall frost.

Decrease the incidence of crabgrass without chemicals:

  • Keep a healthy lawn. Keeping the grass healthy will keep it dense and have less surface area for opportunistic weeds such as crabgrass to invade. 
  • Use the correct fertilizer and watering program for each season, if not, you could be placing undue stress on your lawn. 
  • Raise your mower height to 2 1/2 to 3 inches during the warmer months. This will increase shade on the soil surface and decrease the chance of the crabgrass seeds from germinating.

Apply Crabgrass Preventer in spring:

  • A spring application of crabgrass preventer destroys crabgrass seeds as they start to germinate which makes them unable to take root and emerge from the soil. 
  • It is important to apply this chemical when soil temperatures are at 55 degrees ensuring the product is applied before the seeds have time to germinate, which is when the soil temperature reaches 62 degrees.
  • Read all directions on the package before you apply.
  • Water in the product after you have applied it.

After the seeds have germinated, a pre-emergent (before the plant emerges from the soil), will no longer be effective. There are only a select number of products that can be applied along with reseeding, ask one of our turf experts if you have any questions. More on lawn care from the University of Minnesota Extension.

Post-emergent herbicides for crabgrass

There are chemicals that can kill crabgrass but it can also kill your lawn if not applied correctly. We carry a product that is helpful. Learn more here. Visit our friendly knowledgeable lawn and garden experts for more information on the best way to restore your lawn if crabgrass has completely taken over. Read more on Post-emergent care here

The experts at Gertens are always available to answer your questions!