Overseeding 5,000 square feet of tall fescue takes about 20 pounds of seed, while a new lawn of the same size takes about 40.
How the grass seed calculator works
GrassSeedCalc multiplies your lawn area in thousands of square feet by the seeding rate for the grass you choose. The rates are midpoints of the ranges published by US university extension services, in pounds of pure, uncoated seed per 1,000 square feet: the full rate for a new lawn on bare soil, and about half for overseeding an existing lawn. Coated seed can be up to half coating by weight, so the coated option doubles the rate. Bags are rounded up to whole bags, and the per-acre figure is the rate × 43.56, since an acre is 43,560 square feet. Areas in acres or square metres are converted to square feet first.
Seeding rates by grass type
| Grass | New lawn (lb/1,000 sq ft) | Overseed (lb/1,000 sq ft) | New lawn (lb/acre) | Type |
|---|---|---|---|---|
| Tall fescue | 8 | 4 | 348 | cool-season |
| Kentucky bluegrass | 2.5 | 1.5 | 109 | cool-season |
| Perennial ryegrass | 7 | 4 | 305 | cool-season |
| Fine fescue | 4.5 | 2.5 | 196 | cool-season |
| Sun & shade mix | 5 | 2.5 | 218 | cool-season |
| Bermudagrass (hulled) | 1.5 | 1 | 65 | warm-season |
| Zoysiagrass | 1.5 | 1 | 65 | warm-season |
| Centipedegrass | 0.5 | 0.25 | 22 | warm-season |
| Bahiagrass | 8 | 5 | 348 | warm-season |
| Buffalograss | 2.5 | 1.5 | 109 | warm-season |
Follow the rate on your seed bag when it differs: blends, mixes and seed quality vary. Germination needs good seed-to-soil contact and steady moisture. Results are estimates.
Frequently asked questions
How much grass seed do I need per square foot?
It depends on the grass: about 8 lb per 1,000 sq ft for a new tall fescue lawn, 2.5 lb for Kentucky bluegrass and 7 lb for perennial ryegrass. Overseeding uses about half.
Can I put down too much grass seed?
Yes. Seedlings crowded too close compete for water and light and are more prone to disease, so more is not better.
Why does coated seed need a higher rate?
The coating can be up to half the weight, so you need about twice the pounds to sow the same number of seeds.
Is GrassSeedCalc free?
Yes, with no sign-up or ads.
Are my numbers saved?
Yes, in this browser only.