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How to sow grass seed UK

Updated: October 2026

You already have a bag, and the remaining risk is the calendar and the rate. A warm-week review, a four-day claim, or an overseeding coverage title can put seed down at the wrong time or too thinly on bare soil. How to sow grass seed UK, for a domestic lawn, means the Royal Horticultural Society windows, a gram rate you can check, moisture, a plan for birds, and a first cut based on height. The [grass seed comparison](/hub/seeds-and-plants/grass-seed) is where the twelve listings and prices sit. This page does not rank bags. EquiGrass is not the worked example. We updated this method in October 2026. It is not a germination trial. A qualifying purchase through our links can earn a commission at no extra cost to you.

You already have a bag, and the remaining risk is the calendar and the rate. A warm-week review, a four-day claim, or an overseeding coverage title can put seed down at the wrong time or too thinly on bare soil.

Our top picks

Miracle-Gro Miracle-Gro multi-purpose 5 kg

Best overall

Miracle-Gro Miracle-Gro multi-purpose 5 kg
9.1/10about £28.94
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Miracle-Gro Miracle-Gro multi-purpose 500 g

Preis-Tipp

Miracle-Gro Miracle-Gro multi-purpose 500 g
8.8/10about £7.90
View offer
GroundMaster GroundMaster hard wearing 1.5 kg

Alternative

GroundMaster GroundMaster hard wearing 1.5 kg
8.5/10about £14.99
View offer
On this page
  1. 1.Sow in early autumn or mid-spring
  2. 2.Match the grams to a new lawn, an overseed, or a bare patch
  3. 3.Keep the seed moist, and plan for birds
  4. 4.The first cut, and when to stop

Sow in early autumn or mid-spring

The RHS page on starting a lawn from seed puts the useful windows at September to November or March to April, and early autumn is preferred. Soil is still warm, and rain is more reliable than in a dry May. Do not sow in a hot dry spell, and do not sow in summer because one review said a July scattering worked. That is one garden, not a calendar. A Lawns Direct line that prints March to May and August to October is the seller’s field, not a wider season. Germination on the RHS page is often 7–10 days. That is a typical interval, not the four-day claim on EverGreen Fast Grass. That 480 g pack states four days and gives no coverage. Do not expect the claim in a cold week. If you have not chosen the job yet, use how to choose grass seed.

Match the grams to a new lawn, an overseed, or a bare patch

Seed has to touch soil. Sowing onto moss, or onto thatch you have not opened, wastes the bag. RHS repair guidance is usually about 15–25 g/m². Rolawn cites about 23 g/m² for overseeding and about 35 g/m² on bare patches. Use those as checks. If your packet prints a rate, follow the packet. GroundMaster’s 1.5 kg bag states up to 90 m² for overseeding, not for bare soil. The Gro-Sure 300 g box states 10 m². Miracle-Gro 500 g states about 17 m². The shady box states 28 m². The 5 kg bag states up to 165 m². Gro-Sure Smart puts 250 m² in the title. Use 250 m², not a car-parking slogan. UKGROW has no usable area, because a 100 g title conflicts with a 5,000 g unit count. Several ProGrass bags and Fast Grass state no area, so you work in grams. A heavy rose on a watering can drifts seed into lines. That is a spreading mistake, not a brand fault.
Miracle-Gro Miracle-Gro multi-purpose 5 kg

Testsieger

Miracle-Gro Miracle-Gro multi-purpose 5 kg
9.1/10about £28.94
View offer

Keep the seed moist, and plan for birds

Water new seedlings. The surface should not bake, and it should not sit as a puddle that washes seed into the path. An established lawn that has gone brown in drought is a different case. RHS drought-care guidance says those lawns often recover without mains water. That is not a reason to leave a new sowing dry. The Gro-Sure 300 g box carries a bird-deterrent dressing. Do not invent that dressing on the other bags. Headstart Gold and the aqua gel on Gro-Sure Smart are coatings, not a method, and they do not replace soil contact. A light cover that still lets water through is a practical step where birds are heavy. If the spot is under trees, read grass seed for shade before you treat this as an ordinary sow.

The first cut, and when to stop

The RHS starting-a-lawn guidance puts the first cut at about 5–7.5 cm, and says to remove about one third of the height. Mow when the soil is firm enough that the mower does not tear the seedlings out. A fine lawn and a hardwearing lawn share that first cut. How tough they are later belongs on hardwearing vs fine grass seed. Stop when the ground stays waterlogged, when a paddock mix is unreadable and horses will graze it, when a deeply shaded patch has already failed twice, or when a pitch needs certification paperwork you do not have. These listings do not show a certification label. Do not assume the bag is certified.

Common questions

When should I sow grass seed in the UK?
Sow in September to November or March to April. Early autumn is preferred. Do not sow in a hot dry spell. A seller line of March to May and August to October is not a wider season. If you miss autumn, wait for spring.
Can I sow in summer because a review did?
A summer review is one garden’s weather, not a calendar. Hot, dry spells are what the RHS guidance tells you to avoid. Watering inside the proper window does not turn July into September.
How many grams per square metre should I use?
For a repair, the RHS figure is usually about 15–25 g/m². Bare soil needs more than an overseed rate, and seed must touch soil. If the packet prints a rate, use the packet and treat the published figures as a check.
What does a covers 90 m² title usually mean?
On GroundMaster’s 1.5 kg listing it means up to 90 m² for overseeding, not a new lawn. Using that area on bare ground under-seeds the soil. Where a bag states no area, do not invent one from the weight.
How long do I keep new seed moist?
Keep the surface moist through germination and until the seedlings are ready for the first cut. The RHS interval is often 7–10 days, which is not a promise for every week. A drought-brown established lawn often recovers without mains water. Seedlings do not.
What stops birds taking the seed?
In this set, the bird-deterrent dressing is on the Gro-Sure 300 g box. Headstart Gold and aqua gel are not the same claim. A light cover that lets rain through will not compensate for seed left on moss.
When do I make the first cut, and when should I call someone?
Cut at about 5–7.5 cm and take off about one third, once the ground is firm. Call someone if the lawn stays waterlogged, if horses will graze an unreadable paddock mix, if deep shade has failed twice, or if the site needs certification paperwork. Another bag does not fix those cases.

Related pages

Best grass seed UK

Grass seed

How to choose grass seed before you compare prices

Hardwearing vs fine grass seed: ryegrass or fescue

Grass seed for shade UK only where daylight remains

Sources

Public UK sources and the amazon.co.uk listings in this set, last checked on 17 October 2026.

  1. RHS, Starting a Lawn from Seed (retrieved 17 October 2026)
  2. RHS, Lawns in Shade (retrieved 17 October 2026)
  3. RHS, Repairing Lawns (retrieved 17 October 2026)
  4. RHS, Lawn Care for Drought (retrieved 17 October 2026)
  5. GOV.UK, certify seeds for marketing in England and Wales (retrieved 17 October 2026)
  6. Seed Marketing Regulations 2011 (retrieved 17 October 2026)
  7. Fodder Plant Seed (Scotland) Regulations 2005 (retrieved 17 October 2026)
  8. Rolawn, overseeding (retrieved 17 October 2026)
  9. Lawns Direct EquiGrass paddock mix (retrieved 17 October 2026)