Can I spread grass seed on a lawn treated with herbicides?
There should be information on the label of the herbicide you use as to how it will affect seeding. Generally, you cannot seed for 6 weeks after using a pre-emergent herbicide. Most post-emergent herbicides allow for seeding sooner than 6 weeks. Non-selective herbicides such as Roundup generally allow seeding within 7 days. • When should herbicides be applied? Pre-emergent herbicides should be used when the seeds would naturally germinate. For most lawn weeds, this would be in early-to mid-spring and in late summer. Post-emergent herbicides such as weed-and-feed and Ortho Weed-B-Gone are effective almost anytime, except when it is hot. Non-selective herbicide can be applied any time the weeds are actively growing. Read the instructions on the herbicide you have chosen. You want all liquid herbicides to stay on the foliage for at least 6-8 hours before rain or watering. Some dry formulations are most effective when weeds have water on them. Again, read the instructions. • How should I a
