Published August 14, 2026 · Updated August 23, 2026 · By Tupep
Bermudagrass goes down at about 1.5 pounds per thousand square feet. Tall fescue goes down at about 8. Same area, same goal, more than a fivefold difference in weight. That is not a mistake in one of the recommendations. It is a consequence of how different these seeds are.
The reason is seed count, not grass quality
Grass seed rates are given in pounds because that is how you buy it, but what actually matters is how many seeds land per square inch. Seed size varies enormously between species. Kentucky bluegrass seed is dust. Bahiagrass seed is comparatively enormous. A pound of one contains ten times the seeds of a pound of the other.
The formula
Seeds per square inch = (lb per 1,000 sq ft x seeds per lb) / 144,000
The 144,000 is simply the number of square inches in 1,000 square feet (1,000 x 144). Run this and the pound-based rates stop looking arbitrary.
Rates and what they deliver
| Species | New lawn, lb per 1,000 sq ft | Approx. seeds per lb | Seeds per sq inch | Germination days |
|---|---|---|---|---|
| Kentucky bluegrass | 2 | 2,000,000 | 27.8 | 14 to 28 |
| Perennial ryegrass | 7 | 230,000 | 11.2 | 5 to 10 |
| Tall fescue | 8 | 230,000 | 12.8 | 7 to 14 |
| Fine fescue | 5 | 500,000 | 17.4 | 7 to 14 |
| Bermudagrass, hulled | 1.5 | 1,800,000 | 18.8 | 7 to 21 |
| Zoysiagrass | 1.5 | 1,300,000 | 13.5 | 14 to 28 |
| Bahiagrass | 6 | 170,000 | 7.1 | 21 to 28 |
| Centipedegrass | 0.5 | 400,000 | 1.4 | 14 to 28 |
The pound column spans a factor of sixteen. The seeds per square inch column spans a much narrower band for most of the list, roughly 7 to 28. The remaining differences are not noise either. Species with small, slow, low-vigor seedlings get sown at higher seed counts because a larger share of them will not make it. Species with big vigorous seedlings that fill in by spreading get sown thinner on purpose.
Growth habit changes the target
- Bunch-type grasses such as tall fescue and perennial ryegrass do not spread sideways much. What you sow is roughly what you get, so the stand density depends almost entirely on seeding rate.
- Spreading grasses such as Kentucky bluegrass, bermudagrass, and zoysiagrass fill in by rhizomes or stolons. A thinner stand closes over time on its own, so you sow fewer plants and let them run.
- Centipedegrass is the extreme case. It spreads aggressively and its rate is a fraction of a pound. Sowing it at a fescue rate wastes expensive seed and produces a crowded stand that thins itself out anyway.
Worked example: a mixed-exposure yard
A 3,200 square foot yard split into 2,000 square feet of full sun and 1,200 square feet of shade under mature trees. We are seeding tall fescue in the sun and a fine fescue mix in the shade.
- Sun: 2,000 / 1,000 = 2.0, times 8 lb = 16 lb tall fescue
- Shade: 1,200 / 1,000 = 1.2, times 5 lb = 6 lb fine fescue
- Total: 22 lb across two products
Now look at what happens if you ignore species and use one rate for the whole yard:
| Approach | Total seed | Result |
|---|---|---|
| Correct, rate by zone | 22 lb | Both zones at target density |
| 8 lb per 1,000 everywhere | 25.6 lb | Shade zone 60 percent over-sown, crowded and weak |
| 5 lb per 1,000 everywhere | 16 lb | Sun zone 37 percent thin, weeds fill the gaps |
| 2 lb per 1,000 everywhere | 6.4 lb | Both zones badly under-seeded |
The wrong single rate costs money in one direction or costs you the lawn in the other.
Mixes and blends
Two words we should separate. A blend is several cultivars of one species. A mix is several species in one bag. For a blend, use the species rate directly. For a mix, the bag rate is a weighted compromise and you should follow the bag rather than any single-species number, because the components are present in proportions you cannot see.
One thing to watch in mixes: fast-germinating species establish first and can dominate before slower species get going. That is by design in some products, where the quick component acts as a nurse crop, and it is a defect in others. The label tag lists percentages by weight, and weight percentages understate the presence of small-seeded species dramatically.
Adjustments to the base rate
| Condition | Adjustment |
|---|---|
| Overseeding existing turf | About half the new-lawn rate |
| Broadcasting without soil contact | Add 20 percent |
| Slit seeder, two perpendicular passes | Use full rate, split in half per pass |
| Poor seedbed, cloddy or compacted | Fix the seedbed instead of adding seed |
| Low germination on the tag | Divide by the pure live seed fraction |
Check your region before you buy
Which species belongs on your lot is a regional question first and a preference question second, and the rates above are general planning figures. Recommended rates and the correct planting window vary by species and by region, and the authoritative sources are your regional university extension services. They publish local rate tables and seasonal calendars that reflect your climate and soils. Do not treat any single national number, including ours, as definitive. Check your own regional extension service for the species you intend to plant.
Related guides
- How Much Grass Seed for 1,000 sq ft: New Lawn vs Overseeding
- Fall Overseeding Quantity
- Sod vs Seed Cost Comparison
- How Much Mulch Around Trees Without Killing Them
Sources and Further Reading
Run your own numbers with the Grass Seed Calculator, or browse every tool on the calculators index. Coverage figures and material constants are cross-checked against manufacturer technical data sheets before publication. See our Methodology page for how figures are selected and verified.
Planning estimate only. Results assume standard conditions and are intended for material planning. Verify against your product’s technical data sheet and your local building code before purchasing. Structural, electrical, and gas work should be specified by a licensed professional.
Last updated: August 23, 2026
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