Grass Seed Calculator
Calculate pounds of grass seed for a new lawn or overseeding by grass type, with typical seeding rates per 1,000 square feet.
Add this calculator to your website — get the free widget
How to Calculate
Pounds of seed = lawn area ÷ 1,000 × seeding rate. Rates are single middle-of-range values for new lawns: Kentucky bluegrass 3, tall fescue 7, perennial ryegrass 8, hulled bermuda 1.5 and zoysia 1 lb per 1,000 ft².
Overseeding a thin lawn uses half the new-lawn rate, since some grass is already there. Bare patches inside a lawn should be figured at the full rate.
Seed size is what drives the rate. Bluegrass and bermuda seeds are tiny and go a long way; fescue and ryegrass seeds are large, so they need more pounds for the same coverage.
See our methodology for how every calculator on this site is built.
Worked Example: Overseeding a Fescue Lawn
An 8,000 ft² tall fescue lawn that has thinned out over the summer. You plan to overseed in early September.
- New-lawn rate for tall fescue: 7 lb per 1,000 ft²
- Overseeding rate: 7 × 0.5 = 3.5 lb per 1,000 ft²
- Thousands of square feet: 8,000 ÷ 1,000 = 8
- Seed needed: 8 × 3.5 = 28 lb
Tall fescue is commonly sold in 25 lb and 50 lb bags, so you'd buy one 25 lb bag and a small bag, or one 50 lb bag and save the rest for spring patching in a cool, dry place. If a few patches are completely bare, seed those spots at the full 7 lb rate.
A new lawn on the same 8,000 ft² would take 8 × 7 = 56 lb. Kentucky bluegrass at 3 lb would take only 24 lb, but it is slower to establish and more expensive per pound.
Seeding Rates Used
| Grass | Typical range (new lawn) | Rate used here | Overseeding | Season to plant |
|---|---|---|---|---|
| Kentucky bluegrass | 2–3 lb | 3 lb | 1.5 lb | Late summer to early fall |
| Tall fescue | 6–8 lb | 7 lb | 3.5 lb | Late summer to early fall |
| Perennial ryegrass | 7–9 lb | 8 lb | 4 lb | Fall, or spring in the north |
| Bermuda (hulled) | 1–2 lb | 1.5 lb | 0.75 lb | Late spring to early summer |
| Zoysia | about 1 lb | 1 lb | 0.5 lb | Late spring to early summer |
All rates are pounds per 1,000 ft². Blends follow the rate for the main grass in the mix, which the label lists by weight.
Common Mistakes
Seeding without soil contact
Seed thrown on top of thatch or hard dirt mostly feeds birds. Core aerate or dethatch before overseeding, and rake bare soil loose before seeding a new lawn.
Wrong season
Cool-season seed sown in late spring sprouts and then dies in July heat. Warm-season seed sown in fall won't germinate in cold soil.
Letting it dry out
Seed needs constant moisture until it sprouts. That usually means light watering two or three times a day for the first couple of weeks, then backing off to deeper, less frequent watering.
Using pre-emergent
Most crabgrass preventers also stop grass seed. Don't apply one within about 8 to 12 weeks of seeding unless the product says it is safe for new seed.
Practical Tips
- Spread half the seed in one direction and half at right angles to it for even coverage.
- Use a starter fertilizer at seeding time.
- Hold off on mowing new grass until it is about a third taller than your mowing height.
- Check the label for weed seed and "other crop" content. Cheap seed is often cheap for a reason.
Rough Cost
Tall fescue seed typically runs about $2 to $5 per pound, Kentucky bluegrass $5 to $10, perennial ryegrass $2 to $4, hulled bermuda $8 to $15 and zoysia $15 to $40 per pound. Hydroseeding by a contractor usually costs around $0.10 to $0.20 per square foot.
Sources
Common questions
Frequently Asked Questions
How much grass seed do I need per 1,000 square feet?
For a new lawn, 6 to 8 lb of tall fescue, 7 to 9 lb of perennial ryegrass, 2 to 3 lb of Kentucky bluegrass, or 1 to 2 lb of bermuda.
Can I put down too much grass seed?
Yes. Seedlings that come up too thick compete for light and water and are more prone to disease. Stick close to the label rate.
When is the best time to plant grass seed?
Late summer to early fall for cool-season grasses like fescue and bluegrass. Late spring to early summer for warm-season grasses like bermuda and zoysia.
How long does grass seed take to germinate?
Ryegrass 5 to 10 days, tall fescue 7 to 14, bermuda 7 to 14, Kentucky bluegrass 14 to 30, and zoysia 14 to 21 days in warm soil.
Should I cover grass seed with soil?
Rake it in lightly so it sits about 1/8 to 1/4 in deep, then roll or tamp. A thin layer of straw or peat helps hold moisture on slopes and in hot weather.