Weeds in new lawn - Ask Extension
I'm repairing a large area of our property that was damaged when our septic system had to be replaced. Here's the rough timeline: Late April - rotot...
Knowledgebase
Weeds in new lawn #934221
Asked June 04, 2026, 4:14 PM EDT
I'm repairing a large area of our property that was damaged when our septic system had to be replaced. Here's the rough timeline: Late April - rototilled our semi-sandy non-clay turf; May 4th - put down about 1" of topsoil; May 4th - put down seed & starter fertilizer with broadcast spreader and then softly raked seed/fertilize into topsoil. Immediately after, began regular watering with in-ground irrigation system. The seed is a bluegrass mix from Scotts. About 2-3 weeks later, the new grass became visible. About a week after the grass became visible, the weeds arrived! Based on what I've read, I should wait at least 2 months (for me, that means July 4th) before applying a broadleaf weed killer like Weed-B-Gon. Do you agree or can I apply weed killer sooner? Can you recommend anything else to address the weeds? Appreciate anything you can do to help my infant lawn.
Oakland County Michigan
Expert Response
Good Morning,
Believe it or not, hand-pulling is still one of the best defenses against weeds. Pulling annual weeds before they flower and seed is the simplest way to prevent them from spreading. Hand-pulling is easier when soil is moist. A sharp spade or digger can help do the job. Broadleaf weeds in newly seeded turfgrass areas can be most effectively controlled after the second or third mowing by using traditional broadleaf herbicides such as 2, 4-D, dichlorprop, mecoprop, triclopyr, dicamba or combinations of these materials. When selecting and using an herbicide, read and follow label directions carefully. Young seedlings don’t tolerate herbicides very well and the guideline is usually to wait three "real" mowings before applying any herbicides or in some cases at least 60 days. Real mowings mean you’re actually cutting grass, not just running over the area to trim down any weeds.
Tips for reseeding lawns in spring - Turf
I hope this helps. Thanks for using our service.
Believe it or not, hand-pulling is still one of the best defenses against weeds. Pulling annual weeds before they flower and seed is the simplest way to prevent them from spreading. Hand-pulling is easier when soil is moist. A sharp spade or digger can help do the job. Broadleaf weeds in newly seeded turfgrass areas can be most effectively controlled after the second or third mowing by using traditional broadleaf herbicides such as 2, 4-D, dichlorprop, mecoprop, triclopyr, dicamba or combinations of these materials. When selecting and using an herbicide, read and follow label directions carefully. Young seedlings don’t tolerate herbicides very well and the guideline is usually to wait three "real" mowings before applying any herbicides or in some cases at least 60 days. Real mowings mean you’re actually cutting grass, not just running over the area to trim down any weeds.
Tips for reseeding lawns in spring - Turf
I hope this helps. Thanks for using our service.
