Overseeding lawns consisting of Cool season grasses should be done in late summer or early fall. There are many reasons for this. With fall germination, the young grass will have two or three months to become better established before temperatures drop too low and growth stops. Next spring, the young plants will have another few months to develop deeper roots before the summer heat sets in.
How Much Seed
The amount needed for overseeding lawns are usually recorded on the label. It is different with different seed varieties. The rates can be adjusted depending on the thickness of your lawn. If you currently overseed on an annual basis, less seed is preferred.
- Use 2 to 4 lbs per 1000 sq. ft if your lawns is thick already. It is more of a maintenance activity for thicker lawns.
- When overseeding lawns with open dirt areas and other trouble spots, use 4 to 8 lbs per 1000 sq. ft. For complete renovation, 8 to 12 lbs per 1000 sq. ft. may be needed.
Not Too Much
Thick, vibrant lawns are created over time as plants grow and enlarge. Applying so much seed in an attempt get a super thick lawn in three months may lead to overcrowding as plants mature.
Keeping the Seeds Moist
After overseeding your lawn, the seeds will need moisture to germinate. Keep the soil moist (but not overly wet) by lightly sprinkling two to three times a day throughout the required germination period. Once your grass begins sprouting, you can cut down on the amount of water.
Using a Starter Fertilizer
When overseeding lawns, you may find it necessary to apply a starter fertilizer before or directly after seeding. This is especially true if a soil test says your soil Phosphorus (P) is low. Starter fertilizers will contain higher amounts of phosphorus (Middle number on the bag of fertilizer).