how long should you wait planting grass seed after using weed killer
Waiting to Plant Seed. When you spread an herbicide over your lawn and then decide to patch bare spots, overseed or change your grass type to grow a new species from seed, you should wait at least a month with most pre-emergent weed killers.f you used a crabgrass preventer, that time frame might extend to four months. Check the herbicide manufacturer's label to confirm how long you must wait, as it can differ between herbicide products. The pre-emergent herbicides stop weed seeds from germinating, but they can stop grass seeds as well.