Crabgrass control in newly seeded turf
April 21, 2010
If there is one thing that makes homeowners crabby, it is crabgrass in the lawn.
It is nearly time to apply crabgrass preventer. But wait, what if I am seeding new grass?
Fall is the optimum time to seed cool-season turf-grasses, but if you are in a situation where you must seed this spring you have three options for crabgrass control, but realistically only two. Tupersan is a product that can be used at the time of seeding. It is somewhat less effective than other pre-emergence herbicides, but is safe to the newly seeded grass.
Another product that can be used on newly emerged grass, within two weeks after emergence, is one formulation of Dimension. High Yield Turf and Ornamental Weed and Grass Stopper can be used in this manner. Most formulations of Dimension are not labeled for this.
The third possibility is the old stand-by Dacthal. Dacthal is more effective for crabgrass control, but should not be used until the new seedlings are 1 inch tall.
Unfortunately, Dacthal is almost impossible to find in garden centers and has to be special ordered. If the cool-season grass is not seeded very soon it may be too late to use Dacthal anyway, because the crabgrass may germinate before the turf is 1 inch tall. In any case, the longer you wait to seed, the more difficult it will be to get a successful stand established (again, your chances for success in the fall are much greater).
Both Tupersan and Dacthal give short-term control so an additional application will be necessary about six weeks after the first. On the other hand Dimension is longer lasting.