With the first warm days of spring, don't be too anxious to apply crabgrass control to your lawn. Crabgrass is an annual, warm season, grassy weed. That means that crabgrass comes back each year from seed and this seed does not germinate [1] until the soil temperatures are in the low to mid 60's.

The best way to prevent crabgrass is to use a pre-emergent herbicide. This is often mixed in with a fertilizer and sold as crabgrass preventer [2]. For this herbicide to be effective, it should be applied about two weeks before the crabgrass emerges. In an average year that means about May 15th or, using another indicator, when the lilacs are blooming. Apply this granular product with a fertilizer spreader. You will get a more even distribution if you set the gauge at half the normal rate [3], then spread the product twice - covering the area first in one direction, and then again in a direction 90 degrees from the first - producing a crisscross pattern. As with all granular products, it is important that they be lightly watered in. This increases their effectiveness in the upper layer of the soil where the crabgrass seeds are located. In order to prevent an overuse of this product, try to apply this herbicide selectively to areas of the lawn where crabgrass problems were seen last year.

Remember, when the crabgrass really becomes visible in August, it is then too late, short of hand weeding, to get rid of it. Proper timing and application of a crabgrass preventer are the real keys to success in controlling this nuisance weed.