How to sow grass seed: timing, cover and first cut
Updated: 21 October 2026
You have a bag, or you are about to buy one, and the bare soil looks ready because you have raked it once. Fast seed still fails when you sow it in a heatwave, onto thatch, buried under a thick cap of compost, or left as a buffet for pigeons. This page is the sequence for a new or fully bare area in Britain: when the soil is warm enough, how the seed goes down, how you water, and when the first cut is allowed. Pack choice and prices stay on the [fast growing grass seed comparison](/hub/seeds-and-plants/fast-growing-grass-seed) and the [buying guide](/hub/seeds-and-plants/fast-growing-grass-seed/sub/fast-growing-grass-seed-buying-guide). A thin lawn that still has grass in it belongs on the [overseeding](/hub/seeds-and-plants/fast-growing-grass-seed/sub/fast-growing-grass-seed-overseeding) page.
You have a bag, or you are about to buy one, and the bare soil looks ready because you have raked it once.
You have a bag, or you are about to buy one, and the bare soil looks ready because you have raked it once. Fast seed still fails when you sow it in a heatwave, onto thatch, buried under a thick cap of compost, or left as a buffet for pigeons. This page is the sequence for a new or fully bare area in Britain: when the soil is warm enough, how the seed goes down, how you water, and when the first cut is allowed. Pack choice and prices stay on the fast growing grass seed comparison and the buying guide. A thin lawn that still has grass in it belongs on the overseeding page.
Our top picks
| Badge | Product | Stated area | Germination claim | Pack weight | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Miracle-Gro Miracle-Gro EverGreen Fast Grass, 480 g | None printed | 4 days on the listing | 480 g | 8.8 | about £7.67 | View offer |
| Best value |  Westland Gro-Sure Aqua Gel coated seed, 10 kg | 250 m² | Not stated in days | 10 kg | 8.3 | about £56.70 | View offer |
| Alternative |  UK GROW UKgrow fast grow seed, 20 m² | 20 m² | 5–7 days | 600 g | 8.0 | about £9.99 | View offer |
On this page
When the soil is ready
The reliable windows are early autumn, then mid-spring. Autumn gives warm soil and cooler air, so the seed can root before a dry June. October is late. The RHS says sow in October only where the soil is still at least 7°C, which is more realistic in milder parts of England and Wales than on a cold northern plot.
A heatwave is the failure that shows up across this set. EverGreen, Grassias, ProGrass and Gro-Sure reviews include thin or absent germination when the month was hot and dry, even when someone watered. If you cannot keep the top centimetre damp, store the bag. Do not water an established, drought-brown lawn back to green as a habit. A new sowing is the opposite: once it has germinated, it has to stay moist.
A new lawn often wants roughly 25–50 g per square metre as a supplier rule of thumb, and your packet rate overrides that. EverGreen’s 480 g pouch states no square metres, so you cannot assume it covers a whole garden. If water sits for days, or the levels run towards the house, more seed will not fix drainage.
How to put the seed down
Clear weeds and stones, and break the surface so the seed touches soil rather than dead grass. Firm the bed, then rake a crumb on top. Split the seed in half. Sow one half in one direction and the other half at right angles, which is the RHS way of avoiding bare stripes. A 4 metre by 5 metre patch is 20 square metres. At 35 g per square metre that is 700 g, 350 g each way. Weigh it.
Cover lightly. One Gro-Sure review says seed left on the surface and seed buried too deep both did nothing, and about 1 cm of cover was the difference. A thick compost blanket is how several ProGrass reviews ended with almost no new growth. For birds, the RHS suggests fleece, bird tape, or about 50 per cent more seed. A blue coating is only a claim. Keep pets off loose seed. Pet friendly means the seller is not describing a pesticide.
If you are sowing under trees, read the shade page before you commit a fast ryegrass mix. The technique still applies in light shade, and the species may be wrong.
Water, then the first cut
Water with a fine rose so you do not wash the seed into heaps. The aim is a moist surface, not a puddle. After germination, the RHS expects you to keep a new sowing moist. Reviews that report shoots in about five to ten days are describing that first green, not a finished lawn. A four-day bullet on EverGreen or Quick GRO is a listing claim. Plan for about seven to ten days, and do not rebuy on day five.
The first cut comes when the seedlings are about 5–7.5 cm tall. Take off about one third, with a sharp blade, on a dry day. An autumn sowing may not need another cut until spring. The RHS suggests light use for about eight months. If you need a surface within weeks, turf is the honest alternative.
If it does not come up
Wait a full fortnight before you decide the bag was empty, unless the seed was eaten or washed away. Then check four things. Was the soil warm enough, or did you sow into a cold October? Did the seed sit on thatch or under a thick cap? Did birds clear it? Did the surface bake between waterings? Those are the patterns in the review files, including buyers who netted against birds and still saw nothing.
A second bag helps only after one of those causes has changed. If water sits or the soil smells sour, stop buying seed and get the drainage looked at. If you used a weed and moss killer recently, leave the gap on that product’s label. One supplier’s rule of thumb is about four weeks, and it is not a law.
Common questions
When should I sow in the UK?
Early autumn is the first choice, mid-spring the second. October only if the soil is at least 7°C, which the RHS treats as a mild-region limit. Do not sow into a heatwave you cannot water through. A fast title does not move those dates. If the soil feels icy rather than alive, wait for the next window.
How do I spread the seed evenly?
Divide the amount in half, sow one half in one direction and the other half at right angles, and weigh it against the packet rate. On 20 square metres at 35 g per square metre you need 700 g, not a guessed handful. Stripes of bare ground are usually a walking pattern, not bad seed.
How deep should it be covered?
Keep the cover light, around a centimetre in the Gro-Sure review that compared surface seed with seed buried too deep. Rake it in or use a thin topdressing. A thick compost layer is a common way to lose the sowing, and leaving it fully exposed feeds birds.
How do I stop birds?
Use fleece or bird tape, or sow about 50 per cent more seed, which is the RHS suggestion. A bird-deterrent coating is only a listing claim. Keep the cover on until the seedlings are up, and do not rely on a blue dye alone. A Gro-Sure buyer still covered seed with fine sand.
When is the first cut?
When the grass is about 5–7.5 cm, remove about one third with a sharp blade, and do it dry. An autumn sow may then sit until spring. Do not take a heavy first cut because the lawn looks long. Treat the new lawn gently for about eight months. Green shoots at ten days are not a play surface.
How often do I water?
Often enough that the surface stays moist, with a fine rose, especially once you see germination. Puddles wash seed into corners. An established brown lawn is a different RHS decision. A new sowing is the one you keep damp. Do not let the top centimetre bake in a warm spell before the seed is up.
Related pages
Sources
Sources taken from the research digest. Listings were checked in October 2026.
- RHS — Starting a lawn from seed (retrieved 21.10.2026)
- RHS — Lawns in shade (retrieved 21.10.2026)
- RHS — Repairing lawns (retrieved 21.10.2026)
- RHS — October lawns (retrieved 21.10.2026)
- RHS — Lawn drought care (retrieved 21.10.2026)
- Seed Marketing Regulations 2011 (retrieved 21.10.2026)
- GOV.UK — Certify seeds for marketing in England and Wales (retrieved 21.10.2026)
- Love The Garden — How to sow grass seed (retrieved 21.10.2026)
- Boston Seeds — Overseeding an existing lawn (retrieved 21.10.2026)
- amazon.co.uk listings for the twelve ASINs in this comparison (retrieved 21.10.2026)