How Much Grass Seed Do I Need? Rates by Grass Type

Grass seed is sold by the pound, but lawns are measured in square feet, and seeding rates differ by a factor of ten between species. Kentucky bluegrass seed is tiny, so a pound has millions of seeds; tall fescue seed is much larger. That's why one rate can't fit every lawn.

This guide gives seeding rates for common grass types, shows how to convert them to pounds for your lawn, and covers the difference between starting from scratch and overseeding. To get the area right first, the garden calculator helps you work out square footage.

How much grass seed do you need per 1,000 square feet?

Seeding rates are per 1,000 sq ft and depend mostly on seed size and how quickly the grass fills in. These figures reflect typical extension recommendations. If your bag gives a different rate, the bag wins, since coated seed and blends change the math.

St. Augustinegrass is not grown from seed in most home lawns; it is planted as sod, plugs or sprigs. If your yard is shady, look for a shade mix, but expect the rate to be at the higher end.

How many pounds of seed do you need for your lawn size?

Multiply your lawn's area by the rate. Here are the amounts for typical lawn sizes, using the new-lawn rates above. For overseeding, use the lower number in the overseeding column instead.

Example: a 5,000 sq ft tall fescue lawn being overseeded needs 5 × 3–4 lb = 15–20 lb. The same lawn started from bare soil needs 5 × 6–8 = 30–40 lb.

What is the difference between a new lawn and overseeding?

A new lawn starts from bare, prepared soil, so seed has to produce 100% of the turf. Use the full rate. Overseeding adds seed into an existing lawn to thicken it or fix thin patches. The existing grass fills in part of the area, so about half the rate is plenty. Going heavier just causes seedlings to compete and die off.

For small bare spots, a good starting point is the new-lawn rate, since there is no grass there to help.

How do you spread grass seed evenly?

1. Prepare the soil. For a new lawn, loosen the top 4–6 inches, remove rocks and rake smooth. For overseeding, mow low and rake out dead grass so seed touches soil.
2. Measure and weigh. Calculate your pounds and set aside half for the first pass. A cheap kitchen or luggage scale works.
3. Set the spreader. Use the setting on the bag, then spread half the seed walking one direction.
4. Spread the second half crosswise. A perpendicular pass fills gaps.
5. Rake in lightly so seed is about 1/4 inch deep. Most grass seed needs light and soil contact to germinate.
6. Roll or press, then mulch. A thin layer of straw (about 1 bale per 1,000 sq ft, with seed still visible) holds moisture. Water lightly several times a day until seedlings are up.

What do the numbers on a grass seed bag mean?

Look at the label's "analysis" panel. It lists the percentage of each variety, pure seed, inert matter, weed seed and germination, plus a test date. Good seed has at least 85% germination, under 0.5% weed seed and a test date within the last year. Cheap mixes often contain a high percentage of annual ryegrass or "other crop," which is a fast cover but not a lasting lawn.

If the bag is coated seed, its weight includes the coating, so you may need to apply more by weight than the uncoated figure. Check the bag's coverage statement.

What seeding mistakes waste seed and money?

1. Seeding at the wrong time. Seed sprouts best when soil temperatures are right: for cool-season grass, early fall; for warm-season grass, late spring.
2. Using too much seed. Overcrowded seedlings are thin and prone to disease.
3. Burying seed too deep. More than 1/4 to 1/2 inch of soil on top keeps many seeds from emerging.
4. Letting it dry out. Seed that begins to germinate and then dries dies. Keep the top inch moist.
5. Buying by price, not label. A $20 bag with 50% filler covers less than a $30 bag of pure seed.

Should you use seed, sod or plugs?

Seed is the cheapest way to start a lawn, but it needs the most patience and the most watering. Sod gives an instant lawn but costs several times more per square foot. Plugs and sprigs are common for warm-season grasses that spread by runners, such as Bermuda, zoysia and St. Augustine.

How do you care for new grass seedlings?

The first six weeks decide the lawn. Keep the seedbed moist but not soggy, then taper as roots deepen.

• Days 1–14: water lightly two or three times a day to keep the top inch damp. Do not let it dry out.
• Weeks 3–4: cut back to once a day or every other day with longer sessions as seedlings appear.
• First mowing: when grass reaches about 3–4 inches, with a sharp blade, removing no more than one third of the height.
• After four mowings: switch to normal deep, infrequent watering and apply a regular fertilizer if the schedule calls for it.
• Foot traffic: keep it off the area as much as possible until the lawn has been mowed several times.

Unused grass seed stays viable for roughly a year or two if kept cool and dry. Check the test date on the label and avoid seed that has been stored in a hot garage.

Frequently asked questions

The bottom line

Pick your grass, find its rate per 1,000 sq ft, and multiply by your lawn area. For a new lawn, use the full rate; for overseeding, use about half. Measure carefully, split the seed into two passes and keep it moist until it comes up. The garden calculator helps with the area step.

Related tools: Lawn Fertilizer Calculator · Irrigation Runtime Calculator · Topsoil & Gravel Calculator