Never apply pre-emergent if you plan to overseed

What to Do

If you need to seed bare patches or overseed thin areas in spring, do not apply pre-emergent herbicide to those areas. Pre-emergent kills all germinating seeds, including grass seed.

Why It Works

Pre-emergent herbicides do not distinguish between weed seeds and grass seeds. Applying pre-emergent and then seeding is the most common and frustrating spring lawn care mistake. The chemical barrier prevents your grass seed from establishing roots.

Tips

• You can apply pre-emergent to the rest of the lawn and skip the areas being seeded.
• Dithiopyr (Dimension) has the shortest residual if you need to seed later in the season.
• The best approach is to overseed in fall and use pre-emergent in spring, avoiding the conflict entirely.