Crabgrass – Control after Sprouting

Q: I have had an eruption of crabgrass in my lawn this spring. I fertilize regularly and I put down a pre-emergent early this year. Can you suggest any products and treatments to eradicate this stuff?

A: I’m doubtful that you already see crabgrass seedlings in late March since they should still be quite tiny. However, put down another pre-emergent application now and remember to do it in March every year. That should bring it under control even if a few seed have already sprouted this spring. Dithiopyr (click for sources) will kill small, emerged crabgrass seedlings if you are positive crabgrass has already emerged.