Hi Carla-

Applying preemergent crabgrass killer at the appropriate time, properly identifying this weed, and attention to good cultural practices, are the start of a plan to rid your lawn of crabgrass.

I have attached a few articles below that talk about the timing. Using a tool known as GDD tracker, the optimum time to attack with a preemergent crabgrass killer this year, will begin on 3/20, 21, 22-2025—this week. Crabgrass belongs to a group of plants known as summer annuals. These plants will last only one season, and are killed off with a killing frost in the fall and winter months. This is why your window for treating your crabgrass is so important.

Crabgrass that has not been treated with a preemergent, and allowed to grow will produce large amounts of seed that can remain dormant in the ground for several years. Weak turf grass with open ground provides a great space for the dormant seeds to grow. A thick, healthy turf is the best defense against these sprouting seeds.

The “Go Green” Lawncare tip sheet attached below, gives you some guidelines to grow your own thick healthy turf:

• Mowing your lawn at your lawn mowers highest setting. 3-4” high
• A good fertilizer schedule, following a soil test (homesoiltest.msu.edu) that will tell you exactly what your lawn needs, and --
• Smart watering

A good, healthy turf will choke out the weeds.

There are a few post-emergent herbicides, that are mentioned also, however they each come with their own difficulties and disadvantages.

Again, the best defense against crabgrass is the use of a preemergent and a thick healthy turf. Hope this helps.

Always read and follow the package directions for applying a preemergent crabgrass killer.

https://www.canr.msu.edu/resources/go_green_lawncare_tip_sheet

https://www.canr.msu.edu/resources/crabgrass-control-in-home-lawns

https://gddtracker.msu.edu/

https://www.canr.msu.edu/news/timing_crabgrass_pre_emergence_applications