Published August 12, 2026 · Updated August 23, 2026 · By Tupep
The bag tells you a coverage figure. It is usually one number for a blend that contains several species, and it rarely says whether it assumes bare soil or existing turf. Those two situations need very different quantities, and the difference is roughly a factor of two.
The formula
Pounds of seed = (area in sq ft / 1,000) x rate in lb per 1,000 sq ft
For a fixed 1,000 square feet the area term is 1, so the whole job reduces to picking the right rate. Two things set it: the species, and whether you are starting from bare soil or thickening an existing stand.
The general relationship holds across species: overseeding rate is about half the new-lawn rate. New seeding has to establish a complete stand from nothing. Overseeding only has to fill gaps between plants that already exist.
Rates for 1,000 sq ft
These are working ranges, not prescriptions. Notice the spread. Rates differ across species by roughly a factor of three among common lawn grasses, and considerably more once you include the extremes.
| Species | New lawn, lb per 1,000 sq ft | Overseeding, lb per 1,000 sq ft | Cost at $4.50/lb, new lawn |
|---|---|---|---|
| Kentucky bluegrass | 2 | 1 | $9.00 |
| Perennial ryegrass | 7 | 3.5 | $31.50 |
| Tall fescue | 8 | 4 | $36.00 |
| Fine fescue | 5 | 2.5 | $22.50 |
| Bermudagrass, hulled | 1.5 | 0.75 | $6.75 |
| Zoysiagrass | 1.5 | 0.75 | $6.75 |
| Bahiagrass | 6 | 3 | $27.00 |
| Centipedegrass | 0.5 | 0.25 | $2.25 |
Worked example: tall fescue on 1,000 sq ft
New lawn, bare soil: 1,000 / 1,000 = 1, times 8 lb per 1,000 = 8 lb.
Overseeding thin existing turf: 1 x 4 lb per 1,000 = 4 lb.
That is the headline answer, and for most people it is enough. But there is one more adjustment worth making, because 8 lb of bagged product is not 8 lb of seed that will grow.
Pure live seed
Every bag carries a label tag with two numbers that matter: percent pure seed and percent germination. Multiply them to get pure live seed, the fraction of the bag that is actually viable seed of the species you wanted.
PLS fraction = percent pure seed x percent germination
Bagged pounds to buy = target pounds / PLS fraction
Say the tag reads 96 percent pure seed and 88 percent germination.
- PLS = 0.96 x 0.88 = 0.845
- To deliver 8 lb of live seed: 8 / 0.845 = 9.47 lb, so buy 9.5 lb
- For the 4 lb overseed: 4 / 0.845 = 4.73 lb, so buy 5 lb
That is 18 percent more product than the naive number. On a small lawn it is a few dollars. Across an acre it is a bag and a half. We check the tag on every purchase, because two bags on the same shelf at the same price can differ by ten points of germination.
Converting to bags you can actually buy
| Bag size | Covers, new lawn at 8 lb/1,000 | Covers, overseed at 4 lb/1,000 |
|---|---|---|
| 3 lb box | 375 sq ft | 750 sq ft |
| 7 lb bag | 875 sq ft | 1,750 sq ft |
| 20 lb bag | 2,500 sq ft | 5,000 sq ft |
| 50 lb bag | 6,250 sq ft | 12,500 sq ft |
For our 1,000 square foot new lawn, one 7 lb bag plus one 3 lb box gets you to 10 lb, which comfortably covers the 9.5 lb PLS-adjusted target. For the overseed, a single 7 lb bag does it with margin.
Why more is not better
Doubling the rate feels like insurance and it is the opposite. Seedlings crowded too tightly compete for light, water, and nutrients, produce thin weak plants with poor root systems, and become a mat that damps off in the first humid stretch. Overseeded lawns sown too heavily also choke the existing turf you were trying to help. Hit the rate, do not exceed it.
Getting the rate onto the ground evenly
- Split the total into two halves and spread in perpendicular passes. Half the seed north to south, half east to west. This hides spreader calibration error and eliminates stripes.
- Calibrate on a tarp. Set the spreader, walk a measured 100 square feet, sweep up and weigh what came out, then scale.
- Broadcast seed sitting on top of thatch never germinates. Rake, dethatch, or core aerate first so the seed reaches soil.
- Roll or drag lightly after spreading. Seed to soil contact matters more than the exact rate.
Where the real answer comes from
Rates and planting windows vary by species and by region, and the authoritative sources for both are your regional university extension services. They publish species-specific rates for local conditions, and those numbers can differ meaningfully from any national figure, including the ranges in the table above. Treat what we have given you as a planning framework and check your own regional extension service for the number that applies to your grass in your area.
Related guides
- Seeding Rates by Grass Type
- Fall Overseeding Quantity
- How Many Pallets of Sod for a 5,000 sq ft Yard
- 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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