Grass seed calculator
Seeding rates vary from 1 pound per 1,000 square feet for Bermuda to 8 pounds for tall fescue, so the grass type matters more than the lawn size. Pick the seed, say whether you are starting fresh or overseeding, and get the pounds and bags to buy.
How the grass seed calculator works
Seed is applied at a rate measured in pounds per 1,000 square feet, and that rate is set by the grass species. Large-seeded grasses like tall fescue and ryegrass need 6 to 8 pounds for a new lawn, while tiny-seeded bluegrass needs only 2 to 3. Overseeding into existing turf uses about half the new-lawn rate because the established grass fills in the gaps.
The calculator divides your lawn area by 1,000, multiplies by the rate for the grass and job you picked, then rounds up to whole bags. A rough starter fertilizer estimate is included at 4 pounds of product per 1,000 square feet, which is a common label rate.
Seeding rates used
| Grass | New lawn | Overseed | Best region |
|---|---|---|---|
| Tall fescue | 8 lb | 4 lb | Transition zone, cool |
| Kentucky bluegrass | 3 lb | 1.5 lb | Cool, full sun |
| Perennial ryegrass | 8 lb | 4 lb | Cool, quick cover |
| Fine fescue | 5 lb | 2.5 lb | Cool, shade |
| Bermuda (hulled) | 1.5 lb | 0.75 lb | Warm, full sun |
| Zoysia | 2 lb | 1 lb | Warm |
| Centipede | 0.5 lb | 0.25 lb | Southeast, acidic soil |
| Buffalograss | 3 lb | 1.5 lb | Plains, low water |
Rates are per 1,000 square feet and reflect university extension recommendations. Follow the bag label when it differs; some blends include fertilizer or mulch that change the spread rate.
Getting seed to take
- Seed cool-season grasses in late August through September, when soil is warm and weeds are fading. Spring is second best. Seed warm-season grasses in late spring once soil tops 65 °F.
- Loosen the top inch of soil with a rake or core aerator so seed touches dirt. Seed sitting on thatch dries out and dies.
- Spread half the seed walking one direction and half at a right angle for even coverage.
- Water lightly two or three times a day until germination, then deeper and less often.
- Spreading new topsoil first? Use the topsoil calculator. Want instant results? Compare with the sod calculator.
Common sizes, already worked out
Common questions
How much grass seed do I need for 1,000 square feet?
Between 1 and 8 pounds depending on the grass. Tall fescue and ryegrass need about 8 pounds for a new lawn; Kentucky bluegrass about 3; Bermuda 1 to 2. Overseeding takes roughly half.
How much does a 50 lb bag of grass seed cover?
About 6,000 square feet of new tall fescue lawn, 12,000 square feet of overseeding, or 16,000 square feet of new Kentucky bluegrass. The bag label states the coverage for that specific product.
Can I put down too much grass seed?
Yes. Seedlings crowded at double the rate compete for light and water, grow thin and weak, and are more prone to disease. Stick to the label rate and spread it evenly instead of piling on extra.
Should I overseed or start over?
Overseed if more than half the lawn is healthy grass. If the lawn is mostly weeds or bare dirt, kill it off, prepare the soil, and seed at the new-lawn rate for a better result.