How much grass seed do I need?
Enter your lawn size and grass type. The rates come from university extension publications, and the page shows the arithmetic underneath. Not sure of the species? Identify your grass first.
The published rates
Seeding rate is per 1,000 square feet, and it is a ceiling rather than a dial: seedlings packed in past the rate compete with each other and the stand thins itself out.
| Grass | New lawn | Overseeding |
|---|---|---|
| Kentucky bluegrass | 2–3 lb | 1.5–2 lb |
| Tall fescue | 6–8 lb | same (see below) |
| Perennial ryegrass | 4–5 lb | 4–6 lb |
| Fine fescue | 4–5 lb | same (see below) |
| Bermudagrass (seeded) | 1–2 lb | same (see below) |
| Ryegrass over a warm-season lawn | — | 5–10 lb |
Tall fescue is the honest gap here. Extension services publish an establishment rate for it but not a separate, lower overseeding rate, so this calculator keeps 6–8 lb for both instead of halving a number nobody published.
The formula
pounds = (area in sq ft ÷ 1,000) × rate in lb per 1,000 sq ft
Example. A 50 ft × 40 ft yard is 2,000 sq ft. Overseeding it with Kentucky bluegrass at 1.5–2 lb per 1,000 sq ft gives 3 to 4 lb of seed. Adding Cornell's 20% margin for pure live seed makes it 3.6 to 4.8 lb — so you buy 5 lb.
Questions people actually ask
How much grass seed do I need per 1,000 square feet?
It depends on the species. Penn State Extension puts new seedings at 2–3 lb per 1,000 sq ft for Kentucky bluegrass, 6–8 lb for tall fescue, 4–5 lb for perennial ryegrass and 4–5 lb for fine fescue.
Is the overseeding rate lower than the new-lawn rate?
For Kentucky bluegrass, yes — Penn State lists 1.5–2 lb per 1,000 sq ft for overseeding against 2–3 lb for a new lawn. For tall fescue there is no separate published overseeding rate, so this calculator uses the same 6–8 lb rather than inventing a lower one.
Should I buy extra seed?
Cornell's sports field guide suggests buying about 20% more than the calculated amount, because a bag is not 100% pure live seed. The toggle above applies that margin.
Does more seed give me a thicker lawn?
No. Seedlings crowded past the recommended rate compete with each other for water and light, and the stand thins out on its own. Rate is a ceiling, not a dial.
Sources
- Penn State Extension — Lawn Establishment: seeding rates per 1,000 sq ft by species, and the 4–6 lb renovation rate for perennial ryegrass.
- Penn State Extension — Kentucky Bluegrass: 1.5–2 lb per 1,000 sq ft when overseeding, 3–5 lb for mixtures with ryegrass or fine fescue.
- Virginia Cooperative Extension — Fall Lawn Care: 5–10 lb of pure live ryegrass seed per 1,000 sq ft when overseeding a warm-season lawn.
- NC State Extension — Bermudagrass Lawn Maintenance Calendar: seeded common bermudagrass at 1–2 lb per 1,000 sq ft.
- Cornell University — Seeding rates: buy roughly 20% more than the calculated amount to allow for pure live seed.
Rate tells you how much. Soil temperature tells you when — seed dropped outside the germination window is seed wasted, whatever the bag says. Warm-season grasses use a different window: seeding bermudagrass and zoysia. Sod skips the wait but not the prep — the sod calculator turns your lawn size into pallets at your farm's quoted coverage.