Grass Seed Calculator
Find how many pounds of grass seed your lawn needs, by area and species — for a new lawn or for overseeding. Seeding rates vary enormously between grass types, so species matters more than area.
The rate printed on your seed bag always takes precedence — blends and coated seed differ from straight species.
Seeding rates by species
Pounds per 1,000 square feet. The spread between species is large because seed size varies by more than an order of magnitude — centipede seed is tiny, bahiagrass seed is coarse.
| Species | Season | New lawn | Overseed | Notes |
|---|---|---|---|---|
| Kentucky bluegrass | Cool | 2-3 | 1-1.5 | Fine seed, spreads by rhizomes, self-repairing |
| Tall fescue | Cool | 6-8 | 3-4 | Large seed, drought tolerant, bunch-forming |
| Perennial ryegrass | Cool | 6-9 | 4-5 | Fast germination, often used in mixes |
| Fine fescue | Cool | 4-5 | 2-3 | Shade tolerant, low input |
| Bermuda (hulled) | Warm | 1-2 | 0.5-1 | Very fine seed, aggressive spreader |
| Zoysia | Warm | 1-2 | 0.5-1 | Slow to establish, dense once mature |
| Centipede | Warm | 0.25-0.5 | 0.25 | Extremely fine seed, low fertility needs |
| Bahiagrass | Warm | 5-10 | 3-5 | Coarse, tolerates poor sandy soil |
Seed needed by lawn size
New-lawn quantities for the four most common choices. The final row is a quarter-acre lot.
| Lawn area | Kentucky bluegrass | Tall fescue | Perennial ryegrass | Bermuda |
|---|---|---|---|---|
| 1,000 sq ft | 2-3 lb | 6-8 lb | 6-9 lb | 1-2 lb |
| 2,500 sq ft | 5-8 lb | 15-20 lb | 15-22 lb | 2-5 lb |
| 5,000 sq ft | 10-15 lb | 30-40 lb | 30-45 lb | 5-10 lb |
| 7,500 sq ft | 15-22 lb | 45-60 lb | 45-68 lb | 8-15 lb |
| 10,000 sq ft | 20-30 lb | 60-80 lb | 60-90 lb | 10-20 lb |
| 21,780 sq ft | 44-65 lb | 131-174 lb | 131-196 lb | 22-44 lb |
More seed does not make a better lawn
This is the mistake worth avoiding, and it is counter-intuitive enough that people make it deliberately.
Sowing above the labelled rate produces a worse lawn, not a thicker one. Seedlings germinating shoulder to shoulder compete for the same light, water, and nutrients. The result is spindly grass with shallow roots that struggles in its first drought and is markedly more prone to damping-off and other seedling diseases.
If your lawn is thin, the cause is usually soil compaction, shade, pH, or drainage — not seed quantity. Doubling the seed on compacted clay produces double the seedlings that fail.
Getting the establishment right
- Soil contact matters more than quantity. Seed sitting on thatch will not germinate regardless of rate. Rake, core aerate, or slice-seed so seed reaches soil.
- Timing beats everything. Cool-season grasses sown in late summer establish through autumn with little weed pressure. The same seed sown in late spring competes with crabgrass and then meets summer heat as seedlings.
- Keep the surface damp, not soaked. Light frequent watering until germination, then longer and less often to drive roots down.
- Check the tag for inert matter. Cheap seed can be 20% or more inert filler and may carry weed seed. A bag that costs half as much per pound is not half the price per viable seed.
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
It depends entirely on species. Tall fescue needs 6-8 lb per 1,000 sq ft for a new lawn; Kentucky bluegrass needs only 2-3 lb because the seed is far smaller and it spreads by rhizomes. Always check the rate on your seed bag, which supersedes any general chart.
How much seed for overseeding versus a new lawn?
Overseeding uses roughly half the new-lawn rate, because you are thickening existing turf rather than establishing full cover. Tall fescue drops from 6-8 lb to 3-4 lb per 1,000 sq ft.
How many pounds of grass seed for 5,000 square feet?
For a new tall fescue lawn, 30-40 lb. For Kentucky bluegrass, 10-15 lb. For overseeding fescue, 15-20 lb.
Can I use more seed to get a thicker lawn?
No — over-seeding past the recommended rate makes the lawn worse. Seedlings compete with each other for water, light, and nutrients, producing thin spindly grass with weak roots that is more prone to disease. Stay within the labelled rate.
When should I plant grass seed?
Cool-season grasses (fescue, bluegrass, ryegrass) establish best in late summer to early autumn, with spring as second choice. Warm-season grasses (bermuda, zoysia, centipede) want late spring to early summer once soil is reliably warm.