How to use this calculator
- Pick your grass type. For a blend or mix, choose the last option and enter the rate printed on the bag.
- Choose new lawn or overseeding. Overseeding a thin lawn uses about half the new-lawn rate.
- Add your lawn areas as rectangles, circles or known square feet.
- Enter your bag weight and, optionally, the price.
Seeding rates by grass type
| Grass | New lawn (lb per 1,000 sq ft) |
|---|---|
| Tall fescue | 5 – 8 |
| Kentucky bluegrass | 1½ – 2 |
| Perennial ryegrass | 4 – 6 |
| Fine fescues | 3 – 5 |
| Bermudagrass, hulled | ½ – 1 |
| Bermudagrass, unhulled | 1 – 2 |
| Zoysiagrass | ½ – 3 |
| Centipedegrass | ½ – 3 |
Rates are from University of Tennessee Extension’s guide to seeding turfgrass. The calculator uses the middle of each range as its recommendation and shows the full range too.
The formula
- Seed needed (lb) = seeding rate (lb per 1,000 sq ft) × lawn area (sq ft) ÷ 1,000
- Overseeding uses about half the new-lawn rate
- Bags = seed needed ÷ bag weight, rounded up
Worked example
A new tall fescue lawn made up of a 50 × 40 foot front lawn and a 60 × 50 foot back lawn:
- Area: 2,000 + 3,000 = 5,000 sq ft
- Rate: the middle of 5–8 is 6.5 lb per 1,000 sq ft
- Seed: 6.5 × 5,000 ÷ 1,000 = 32.5 lb (full range 25–40 lb), or 2 bags of 25 lb
- Overseeding the same lawn instead: about 16 lb, so 1 bag
Tips for a good stand of grass
- Sow at the right time. Late summer to early fall for cool-season grasses; late spring to early summer for warm-season grasses.
- Get seed in contact with soil. Rake the soil loose before seeding, then rake lightly or roll afterward so the seed is pressed in.
- Split the seed in two and spread half in one direction and half crosswise for even coverage.
- Keep the surface moist with light, frequent watering until the grass is up, then water more deeply and less often.
- More seed isn’t better. Sowing far above the recommended rate crowds seedlings, which then compete and thin out.
Sources
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
It depends on the grass. University of Tennessee Extension lists 5 to 8 pounds for tall fescue, 1½ to 2 pounds for Kentucky bluegrass, 4 to 6 pounds for perennial ryegrass and ½ to 1 pound for hulled bermudagrass per 1,000 square feet for a new lawn.
How much seed do I need to overseed?
A common rule of thumb is about half the new-lawn rate when overseeding a thin lawn. If your seed bag gives an overseeding rate, use that instead.
Why do grass seeding rates vary so much?
Seed size varies enormously between grasses. A pound of Kentucky bluegrass contains far more seeds than a pound of tall fescue, so you need fewer pounds of bluegrass to get the same number of seeds per square foot.
When is the best time to plant grass seed?
Sow cool-season grasses such as fescue, bluegrass and ryegrass in late summer to early fall, when soil is warm and air is cooling. Sow warm-season grasses such as bermudagrass and zoysiagrass in late spring to early summer, once the soil has warmed.
What is the difference between hulled and unhulled bermudagrass seed?
Hulled seed has had its outer husk removed, so it germinates faster and you need less of it. Unhulled seed is typically sown at about double the hulled rate.