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Grass Seed Calculator: How Much Seed Do I Need?
Calculate pounds of grass seed for a new lawn or for overseeding, using the recommended rate for your grass type, then the number of bags and the cost.
Seeding rates by grass type
Seed rates are given in pounds per 1,000 sq ft. Grasses with tiny seeds, like Kentucky bluegrass and Bermuda, need far fewer pounds than big-seeded tall fescue and ryegrass. Overseeding a thin lawn uses about half the new-lawn rate.
| Grass | New lawn (lb / 1,000 sq ft) | Overseeding |
|---|---|---|
| Tall fescue | 6 to 8 | 3 to 4 |
| Kentucky bluegrass | 2 to 3 | 1 to 2 |
| Perennial ryegrass | 7 to 9 | 3 to 5 |
| Fine fescue | 4 to 5 | 2 to 3 |
| Bermuda (hulled) | 1 to 2 | 0.5 to 1 |
| Zoysia | 1 to 2 | 1 |
| Centipede | 0.25 to 0.5 | 0.25 |
Always check the bag: blends and coated seed have their own rates, and coated seed needs more pounds for the same number of seeds.
Worked example
A 50 × 100 ft yard is 5,000 sq ft. A new tall fescue lawn at 7 lb per 1,000 sq ft needs 35 lb of seed, which is two 20 lb bags. Overseeding the same lawn takes about 20 lb, a single bag.
When to seed
- Cool-season grasses (fescue, bluegrass, ryegrass) grow best from seed in early fall, when the soil is warm and the air cool. Spring is second best.
- Warm-season grasses (Bermuda, zoysia, centipede) should be seeded in late spring to early summer, once soil temperatures stay above 65°F.
Tips for good germination
- Seed must touch soil. Rake bare areas, or core-aerate before overseeding, and lightly rake seed in.
- Keep the top inch of soil moist with light watering once or twice a day until the grass is about 2 in tall.
- Use a starter fertilizer at seeding, and wait to mow until the grass is about one-third taller than your mowing height.
Want instant grass instead? Compare with the sod calculator.
Frequently asked questions
How much grass seed do I need per 1,000 sq ft?
For a new lawn: tall fescue 6 to 8 lb, perennial ryegrass 7 to 9 lb, Kentucky bluegrass 2 to 3 lb, Bermuda 1 to 2 lb. Overseeding takes about half as much.
How much grass seed do I need for an acre?
An acre is 43,560 sq ft. A new tall fescue lawn needs about 300 lb per acre; Kentucky bluegrass about 110 lb.
Can you put down too much grass seed?
Yes. Seeding far above the recommended rate makes seedlings compete for light and water, and the crowded lawn is more prone to disease.