Seeding rates vary 4× between grass types — here's the per-1,000-sq-ft math for each, plus the overseeding discount and a worked example.
"How much seed" has no single answer because grass seed isn't one product. Kentucky bluegrass seed is tiny — there are far more seeds in a pound than in a pound of tall fescue — and bluegrass spreads by underground rhizomes, filling gaps on its own. Fescue is a bunchgrass with big seeds that stays where it's planted. The result: a new bluegrass lawn needs 2–3 lb per 1,000 sq ft, while tall fescue needs 6–8 lb — nearly four times as much per square foot for the same coverage.
The second variable is what you're seeding onto. Bare soil takes the full rate; an existing lawn takes about half. Overseeding only needs to fill gaps between live plants, and seed that lands on established grass never reaches soil anyway. Those two questions — what species, and new lawn or overseed — determine your rate before you touch a calculator.
| Grass Type | New Lawn | Overseeding |
|---|---|---|
| Kentucky Bluegrass Tiny seed — lowest rate of any common lawn grass | 2–3 lb | 1–1.5 lb |
| Tall Fescue Large seed, bunching habit — needs the heaviest rate | 6–8 lb | 3–4 lb |
| Perennial Ryegrass Fast germination, often blended with bluegrass | 6–8 lb | 3–4 lb |
| Fine Fescue Shade-tolerant, moderate rate | 4–5 lb | 2–2.5 lb |
| Bermuda (hulled) Warm-season, spreads aggressively once established | 1–2 lb | 0.5–1 lb |
Typical published rates for pure stands; blends fall between their components' rates. Always check your specific bag's label — coated seed covers less per pound because the coating adds weight.
Say you're renovating 4,000 sq ft of backyard down to bare soil with a sun-and-shade mix. Using Scotts Rapid Grass as the concrete case: its 5.6 lb bag is rated for 2,800 sq ft of new lawn, so 4,000 ÷ 2,800 = 1.43 → two 5.6 lb bags (~$66), with leftover for the inevitable thin patches. The 16 lb bag rated at 8,000 sq ft (~$75) covers the same job in one bag with half left over — worth it if you'll overseed the front yard in fall, not if the bag will sit in the garage for three years losing germination.
Now flip it to overseeding: the same 4,000 sq ft as an existing-but-thin lawn takes roughly half rate, so one 5.6 lb bag does it. This is the most common seed-buying mistake in reverse — people overseed at the new-lawn rate and buy twice the seed, then spread it all, which crowds the seedlings. Half rate isn't the economy option; it's the correct one.
Compare bags on coverage, not weight. Every seed bag's label discloses its composition — the percentages of pure seed, other crop, weed seed, and inert matter, plus the germination rate. Coated products carry a substantial share of their weight as coating rather than seed, which is why a coated bag lists lower coverage per pound than raw seed. Neither is a scam — coatings hold moisture around the seed — but it means the honest comparison between two bags is dollars per square foot of labeled coverage, never dollars per pound.
Seed cost is rarely the real cost, for what it's worth: at these prices you're paying just over a cent per square foot for seed, while starter fertilizer, compost or topsoil for seed-to-soil contact, and water over the 7–21 day germination window typically add more than the seed itself. Timing matters more than any of it — the when to plant guide covers the fall and spring windows by region.
Every rate above multiplies against your actual seeded area. Trace the section you're seeding — not the whole lot — on satellite imagery.
Then run the grass seed calculator for bag counts by rate, or open the measurement tool directly.