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This grass seed calculator works out how many pounds of seed you need for a new lawn or for overseeding. Choose your grass type, enter the lawn area and it applies university-recommended seeding rates per 1,000 square feet and tells you how many bags to buy.
How to Use the Grass Seed Calculator
- Measure the lawn area in square feet.
- Choose the grass type, or enter the rate printed on your seed bag.
- Choose a new lawn or overseeding.
- Enter the bag size.
Grass Seed Formula
Seed (lb) = Lawn area (sq ft) ÷ 1,000 × Seeding rate (lb per 1,000 sq ft)
Seeding Rates for New Lawns
| Grass type | lb per 1,000 sq ft | lb per acre |
|---|---|---|
| Tall fescue | 8–10 | 350–435 |
| Perennial ryegrass | 7–8 | 305–350 |
| Fine fescues | 3–6 | 130–260 |
| Kentucky bluegrass | 2–3 | 87–130 |
Rates are from Ohio State University’s turfgrass establishment guidance. For overseeding a thin lawn, about half the new-lawn rate is a common starting point; follow the bag label for blends and warm-season grasses.
Example
A new 5,000 sq ft tall fescue lawn needs 5 × 8 to 5 × 10 = 40–50 lb of seed, or ten 5 lb bags at the higher rate.
Tips for Seeding a Lawn
- Seed cool-season grasses in late summer to early fall, when soil is warm and weeds are fewer.
- Loosen the top inch of soil and rake the seed in lightly.
- Spread half the seed in one direction and half at right angles for even coverage.
- Keep the seedbed moist with light, frequent watering until the grass is established.
Want an instant lawn instead? Use the sod calculator.
Sources
Frequently Asked Questions
How much grass seed do I need per 1,000 square feet?
It depends on the grass: about 8–10 lb for tall fescue, 7–8 lb for perennial ryegrass, 3–6 lb for fine fescue and 2–3 lb for Kentucky bluegrass.
How much grass seed do I need for an acre?
Multiply the rate per 1,000 sq ft by 43.56. Tall fescue needs about 350–435 lb per acre.
Can I put down too much grass seed?
Yes. Overcrowded seedlings compete for light and water and are more prone to disease.
How much seed for overseeding?
Roughly half the new-lawn rate, depending on how thin the lawn is.
Read the guide: How Much Grass Seed Do I Need? Rates per 1,000 Sq Ft
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