How the grass seed calculator works
Seeding rates are given in pounds of seed per 1,000 square feet. Divide your lawn area by 1,000 and multiply by the rate for your grass.
seed (lb) = lawn area (sq ft) ÷ 1,000 × seeding rate (lb per 1,000 sq ft)
Small-seeded grasses such as Kentucky bluegrass and Bermuda need far fewer pounds than tall fescue or ryegrass, because a pound of tiny seed contains many more seeds. That is why the rate depends so heavily on grass type.
Worked example
A 5,000 sq ft lawn seeded from scratch with tall fescue at a typical 7 lb per 1,000 sq ft needs 5 × 7 = 35 lb of seed, or 15.88 kg. Overseeding the same lawn at half that rate, 3.5 lb per 1,000 sq ft, takes 17.5 lb. In metric, the lawn is 464.5 m² and the new-lawn rate is 34.2 g per m².
Typical seeding rates
These are rules of thumb based on commonly published ranges. The calculator uses the typical value shown; follow your seed label if it differs.
| Grass | New lawn, range | Typical new lawn | Typical overseeding |
|---|---|---|---|
| Tall fescue | 6 to 8 lb | 7 lb (34.2 g/m²) | 3.5 lb (17.1 g/m²) |
| Kentucky bluegrass | 1.5 to 3 lb | 2 lb (9.8 g/m²) | 1 lb (4.9 g/m²) |
| Perennial ryegrass | 5 to 8 lb | 6 lb (29.3 g/m²) | 3 lb (14.6 g/m²) |
| Fine fescues | 3 to 5 lb | 4 lb (19.5 g/m²) | 2 lb (9.8 g/m²) |
| Bermuda grass, hulled | 1 to 2 lb | 1.5 lb (7.3 g/m²) | 0.75 lb (3.7 g/m²) |
| Ryegrass over dormant Bermuda | 5 to 10 lb | 8 lb (39.1 g/m²) | 8 lb (39.1 g/m²) |
Rates are per 1,000 sq ft. Overseeding a thin lawn usually uses about half the new-lawn rate, since existing grass already covers part of the ground. Southern lawns of dormant Bermuda are sometimes overseeded in fall with ryegrass for green winter color; that ryegrass has to cover the whole area, so it uses a full rate.
Matching the grass to your region
| Type | Examples | Best seeding time |
|---|---|---|
| Cool-season | Tall fescue, Kentucky bluegrass, perennial ryegrass, fine fescues | Late summer to early fall; spring is second best |
| Warm-season | Bermuda, zoysia, centipede | Late spring to early summer, once soil is warm |
Cool-season grasses dominate the northern US, Canada and cooler parts of Australia. Warm-season grasses suit the southern US and warmer Australian climates. Areas in between, often called the transition zone, frequently use tall fescue.
Reading a seed label
Two bags of the same grass can perform very differently. The label on the back tells you what you are paying for.
- Variety names. Good bags list named cultivars rather than just the species. Named varieties are bred for color, disease resistance or drought tolerance.
- Germination percentage. The share of seed that sprouted in the lab test. Higher is better.
- Weed seed and other crop seed. Look for low figures. Other crop seed can include coarse grasses you do not want in a lawn.
- Inert matter and coatings. Coated seed weighs more per seed, so the bag covers less area per pound. Follow the coverage printed on that bag.
- Test date. Seed loses viability with age. Buy recent stock and store leftovers cool and dry.
Tips for better germination
- Get seed onto soil. Seed sitting on thatch or old leaves rarely takes. Rake, dethatch or core aerate before overseeding.
- Split the seed. Spread half in one direction and half at right angles for even cover.
- Keep the surface moist. Light, frequent watering until seedlings are established usually works better than occasional heavy soaking.
- Check weed products. Most pre-emergent crabgrass preventers also stop grass seed from germinating. Read the label before using one near seeding time.
- More is not better. Seeding far above the recommended rate crowds seedlings, which then compete with each other and can thin out.
Prefer instant grass? Compare with the sod calculator. Feeding a new lawn? The fertilizer calculator works out how much product gives a set amount of nitrogen.
Frequently asked questions
How much grass seed do I need per 1,000 square feet?
It depends on the grass. Typical new-lawn rates are about 7 lb for tall fescue, 6 lb for perennial ryegrass and 2 lb for Kentucky bluegrass per 1,000 sq ft. Overseeding uses about half.
How many pounds of grass seed for 5,000 square feet?
For a new tall fescue lawn at 7 lb per 1,000 sq ft, 35 lb. For overseeding at 3.5 lb, 17.5 lb.
Should I use the rate on the bag or this calculator?
Use the bag. Blends, coated seed and different cultivars change the rate, and the label is written for that product.
What happens if I put down too much seed?
Seedlings crowd each other, compete for water and light, and can be more prone to disease. Stick close to the recommended rate.