When to Plant Grass Seed

The best time to plant grass seed in the UK is during spring or early autumn. These seasons offer the ideal balance of warmth and moisture, giving the seed the right conditions to germinate and establish. In spring, aim for March to May. In autumn, late August through to mid-October works well. Planting outside of these periods can still succeed but may require more watering, weed control, and care to protect young grass from extremes of temperature or heavy rainfall.

Starting a Lawn from Seed

Starting a lawn from seed is cost-effective and gives you more control over grass type and coverage than laying turf. It’s a flexible option for new builds, patching up worn areas, or even replacing tired, weedy lawns. Sowing seed gives better root establishment than turf in the long run, provided it’s given the right conditions and care during its early stages.

Why and When to Sow

Grass seed germinates best when soil temperatures are above 8°C and there is consistent moisture in the soil. Spring sowing makes sense when you're working on a new garden, but you’ll need to manage weeds more actively. Autumn sowing is often preferred because the soil is still warm from summer, there’s less weed pressure, and rainfall is usually more reliable. Avoid sowing in the height of summer or dead of winter unless you’re prepared to water daily or protect from frost.

Choosing the Right Seed Mix

The best grass seed mix depends on how the lawn will be used. For family gardens with regular foot traffic, choose a hardwearing ryegrass-based mix. For decorative or ornamental lawns, a fine fescue mix offers a softer, greener finish. Shaded areas benefit from mixes containing shade-tolerant species. Some modern blends include a mix of quick-germinating ryegrass with slower-establishing fine grasses for a balance of durability and appearance.

Preparing Your Sowing Site

Proper preparation is key to a healthy lawn. Clear the area of weeds, stones, and debris, then dig or rotovate the soil to a depth of at least 15cm. Rake it level and firm it down by lightly walking over the surface in overlapping steps. Finally, rake again to create a fine, crumbly surface. Allow the ground to settle for a few days before sowing if possible, watering it lightly if dry.

How to Sow a Lawn

Sow grass seed evenly across the area by hand or using a spreader, aiming for the recommended rate on the seed packet. It’s often helpful to sow half in one direction and half at right angles to ensure good coverage. Lightly rake the seed into the soil and water gently but thoroughly. Covering with a thin layer of topsoil is optional but can protect seed from birds and help retain moisture. Keep the area moist until germination, which usually takes 7 to 21 days depending on conditions.

Looking After a New Lawn

Once the seed has germinated, continue to water regularly, especially in dry or windy weather. Don’t allow the soil to dry out completely until the grass is well established. Avoid walking on the new lawn until it has filled out and can withstand light foot traffic. First mowing should be done when the grass reaches about 7–8cm tall, cutting it down to around 5cm. Make sure the mower blade is sharp to avoid pulling out young shoots. Gradually reduce the cutting height as the lawn thickens.

Common Mistakes When Sowing Grass Seed

Sowing grass seed seems simple, but there are a few common errors that can lead to poor germination, patchy lawns, or wasted effort. Here's what to watch out for:

Sowing at the Wrong Time

Seed sown when the soil is too cold, too wet or too dry will struggle to germinate. In the UK, spring and early autumn offer the best chance for success. Trying to seed in mid-summer or winter often leads to failure without serious intervention.

Skipping Soil Prep

Poor soil preparation is one of the biggest reasons new lawns fail. Seed needs a fine, level, weed-free surface to settle into. Lumpy, compacted, or debris-filled ground prevents seed-to-soil contact, which is critical for germination.

Overseeding or Underseeding

Too much seed causes overcrowding and competition, leading to weak, thin grass. Too little seed results in bare patches and more space for weeds. Always follow the application rate on the packet.

Not Raking In the Seed

Grass seed left sitting on the surface can dry out quickly, blow away, or get eaten by birds. Lightly raking the seed into the top layer of soil helps protect it and ensures better contact for germination.

Uneven Watering

Dry patches won’t germinate, and soggy areas may rot the seed. Consistent, even watering is key — especially during the first 2–3 weeks. Once germinated, reduce watering gradually to encourage deep rooting.

Walking on the Seeded Area

Even a few footprints can disrupt emerging seedlings. Use boards or planks if you need to cross the area for watering or maintenance.

Cutting Too Soon or Too Low

First mowing should only happen when the grass is tall enough — usually around 7–8cm. Cutting too soon or scalping the lawn can uproot seedlings and stunt growth.

Grass Seed vs Turf: Which is Better for Your Garden?

Both grass seed and turf have their place, and the right choice depends on your budget, timeline, and how much effort you're willing to put in upfront.

Speed

Turf gives you an instant lawn. You lay it, water it, and within a couple of weeks, it’s usable. Grass seed takes longer — usually 4–8 weeks to become usable, and full coverage can take a season.

Cost

Grass seed is significantly cheaper than turf. Even with soil prep and watering factored in, seed is the go-to for large areas or tighter budgets. Turf is more expensive upfront but saves time.

Flexibility

With seed, you can choose from a wide range of grass types to suit specific conditions — shade, drought, ornamental, high-traffic, etc. Turf offers less choice and is usually a general-purpose ryegrass/fescue blend.

Labour and Prep

Both options require good ground preparation. Turf requires more physical effort on the day, while seed needs more post-sowing care — watering, protection, and patience.

Season and Timing

Seed is best sown in spring or autumn. Turf can be laid most of the year as long as the ground isn’t frozen or waterlogged. Turf also gives you a usable surface sooner, which is a plus for families or pet owners.

Longevity and Rooting

Well-established seed often roots more deeply than turf, which can give it better drought resilience over time. Turf, if laid properly and well-maintained, also establishes strongly and quickly.