How long must you generally wait for before spreading out new seed after putting down crabgrass prevention?

I am not sure really why you must wait, maybe it is something in the crabgrass prevention which may harm the seed?





can you maybe just wait until after a couple of good rains and then safely spread out new seed with starter fertilizer?





Thanks for your answers!

How long must you generally wait for before spreading out new seed after putting down crabgrass prevention?
if, by crabgrass prevention, you mean pre-emergent herbicide, you have to wait because that stuff works by KEEPING SEEDS FROM GERMINATING. Spreading grass seeds down when there is pre-emergent present in the soil is wasting your money. Lots of that seed will be affected.





The longer you wait, the less effective the pre-emergent will be. I recommend 6-8 weeks. I've heard some people recommend as little as 4. You could always try a small spot after X weeks, and if you see mass-germination, then you're good to go!
Reply:Wait at least 4-6 weeks before seeding. You CAN get crabgrass preventer that allows you to seed right away, but it is more expensive. It contains the chemical siduron.





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