Dear Charles,

Thank you for your question regarding when to overseed your lawn. My name is Deborah Hoover and I am a volunteer through the NH Master Gardener program.

The best time to overseed your lawn would be late summer (mid-August to mid-September). This timing will minimize competition from weeds and the soil will still be warm enough to support germination.

If you are just filling in gaps in your lawn, you can do this spring, summer or fall.

Here are a few sources of information from UNH Cooperative Extension and University of Maine Cooperative Extension that may be helpful:

Starting and Overseeding Lawns:

https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource000519_Rep541.pdf

Choosing Seed for the Lawn:

https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource000512_Rep534.pdf

Steps to a Low-Input Healthy Lawn:

https://extension.umaine.edu/publications/2166e/

Lawn Renovation Video:

https://extension.unh.edu/resource/lawn-renovation-video

Thank you for reaching out to Infoline and hope you enjoy happy gardening throughout the growing season!

Please let us know if we can answer any other questions.