A new 1,500 sq ft lawn sown with tall fescue needs about 11.5 lb of seed. That is 7 lb per 1,000 sq ft, plus 10% extra for the edges. In metric, most new lawns need 35 to 50 g of seed per m², so a 10 × 8 m garden (80 m²) needs about 3 to 4 kg.
How much you need depends mainly on the type of grass. A small-seeded grass like Kentucky bluegrass needs far less by weight than a large-seeded one like ryegrass or tall fescue. Here are the usual rates and how to use them.
Seeding rates by grass type
These are typical rates for sowing a new lawn on bare soil. Overseeding a thin lawn uses about half as much.
| Grass type | New lawn (lb per 1,000 sq ft) | New lawn (g per m²) | Overseeding |
|---|---|---|---|
| Kentucky bluegrass | 2–3 | 10–15 | 1–1.5 lb |
| Fine fescues | 3–5 | 15–25 | 2 lb |
| Tall fescue | 6–8 | 30–40 | 3–4 lb |
| Perennial ryegrass | 6–9 | 30–45 | 3–4 lb |
| Bermuda (hulled) | 1–2 | 5–10 | 1 lb |
| Typical UK or AU lawn mix | 7–10 | 35–50 | 15–25 g/m² |
Always check the bag. Seed companies print their own rate, and coated seed can need more by weight because the coating adds weight but no extra seeds.
Handy conversion: 1 lb per 1,000 sq ft is about 4.9 g per m².
How to work it out
- Measure the lawn area. For a rectangle, multiply length by width. Split odd-shaped lawns into rectangles and triangles and add them up. For a circle, use 3.14 × radius × radius.
- Pick the rate for your grass type from the bag or the table above.
- Multiply. Area ÷ 1,000 × rate gives pounds. In metric, area in m² × rate in g gives grams.
- Add 10% for the edges, for any spots you go over twice, and for a little seed kept back to patch bare spots later.
Worked example (US): A 50 × 30 ft lawn is 1,500 sq ft. With tall fescue at 7 lb per 1,000 sq ft, that is 1.5 × 7 = 10.5 lb. Add 10% and you need about 11.5 lb, so buy a 12 lb bag.
Worked example (UK/Australia): A 10 × 8 m lawn is 80 m². At 40 g per m², that is 3.2 kg. Add 10% and you need about 3.5 kg.
The DIYMeter grass seed and turf calculator does this for you, and also works out how much turf you need.
Seed or turf?
- Seed is much cheaper and gives you more choice of grass type. It takes 6 to 10 weeks before you can use the lawn properly, and it needs regular watering while it gets going.
- Turf (sod) gives you a lawn straight away and you can walk on it lightly after 2 to 3 weeks. It costs several times more than seed.
UK turf is usually sold in 1 m² rolls. In the US and Canada, sod is sold in pieces or on pallets that typically cover 400 to 500 sq ft. Order 5% more than the lawn area so you can cut it to fit curves and edges.
Get the soil right first
Seed does best on a firm, level bed of loose topsoil. If you are starting on subsoil or builder’s rubble, spread 4 to 6 inches (10 to 15 cm) of topsoil first. Our guide to how much topsoil you need for a new lawn covers the quantities.
When to sow
- Cool-season grasses (fescues, ryegrass, bluegrass): early autumn is best, while the soil is still warm. Mid-spring is the next best time. This applies to most of the northern US, Canada and the UK.
- Warm-season grasses (Bermuda, zoysia, buffalo, couch): late spring to early summer, once the soil is reliably warm. This applies to the southern US and much of Australia.
Common mistakes
- Sowing too thickly. Doubling the rate doesn’t give you a thicker lawn. The seedlings crowd each other out and are more likely to get disease.
- Sowing it all in one direction. Split the seed in half, sow one half lengthways and the other half across. This avoids stripes and bare patches.
- Letting it dry out. Keep the top layer of soil damp until the grass is about 2 inches (5 cm) tall. That often means watering lightly once or twice a day.
FAQs
How long does grass seed take to germinate? Ryegrass comes up in about 5 to 10 days. Fescues take 7 to 14 days and bluegrass can take 14 to 30 days.
Can I just throw seed on my existing lawn? It works much better if you mow short, rake out thatch and moss, and then seed. The seed needs to touch the soil.
How long does a bag of grass seed last? Stored somewhere cool and dry, seed stays good for two to three years. After that, fewer seeds come up.
Related: the DIY Project Budget & Materials Planner turns your measurements into quantities, costs and a shopping list.
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