How to seed a lawn

Growing and maintaining your garden is a constant project, and knowing how to seed a lawn is the first step towards having thicker, lusher grass. But it’s not a task that’s only suitable for the green-fingered. The secret to seeding your lawn lies in properly preparing the ground before you start since that allows the sprouting seeds the best chance of germination. Seeding a lawn is also a much cheaper option than laying down ready-made turf: good grass seed typically costs between £10-£15 per kilo, which would cover approximately 30 square metres.

To help you get started, we’ve put together a step-by-step guide for starting a lawn from seed, along with all the questions you might have about the topic. We also chatted with David Hedges-Gower, chair of The Lawn Association, and Cassie King at British Garden Centres to learn more about the process of seeding a lawn.

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How to seed a lawn 

“Whether seeding into an existing lawn or starting from scratch, creating an optimal seedbed is essential for successful germination”, David Hedges-Gower told us. Below, we’ve outlined the steps to follow for properly preparing the ground to seed your grass.

Step 1: Prepare the seedbed

Before seeding, Cassie King at British Garden Centres suggests removing debris, weeds and rocks from the soil, then loosening the soil so it opens up. “A scarifier can be used to loosen the top few millimetres of soil, or this can be done with a normal garden rake”, she said.

Cassie also recommends testing the soil’s acidity, which you can easily do with a soil testing kit. “If the pH level is too low, this indicates acidity, and moss is likely to thrive in your soil”, she said. “To increase the pH level, consider using lawn seed mixes that contain calcium carbonate, as this effectively raises the soil’s pH for you.”

Step 2: Check the moisture of the soil

Your soil needs plenty of moisture maintained to a depth of about 10cm: it should dirty your hands easily, but not be muddy enough to stick to your shoes. Getting the soil to this level of moisture might require a few days of watering and then waiting for the surface to dry out.

Step 3: Sow and rake in the grass seed

“Spread the grass seed evenly over the prepared soil and gently rake it in for good seed-to-soil contact”, Cassie said. You can use a seed spreader or your hand to distribute the seed: roughly a handful of seeds will be sufficient per square metre.

Though it may be tempting, don’t use too much seed, as this causes overcrowding and eventually leads to bald patches in the lawn.

Step 4: Roll the soil

Once the seed has mixed in with the soil, gently roll the ground in two directions to firm the soil down, or “gently press it down using your feet or a light roller”, said Cassie. The seeds should only be covered by two to three centimetres of soil to allow their tiny sprouts to push through without being suffocated.

Step 5: Water in the seed

After seeding your lawn, the grass seed needs water to start the germination process, but you don’t want to jostle and move the seeds with a powerful jet stream. Pointing your hose upwards allows water to fall in a rain-like shower, with enough to wet the surface but not a thorough soaking. Alternatively, a lawn sprinkler will do the same job.

Watering daily for the first week will let the seeds get established and stop them from drying out. Once you see signs of germination, you can start watering more heavily and less often.

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How to choose the right grass seed for your lawn

Most grass seeds on the market are a mix of different grass varieties. Typical grasses often include ryegrass, a hard-wearing and versatile grass, fescue, that gives a thicker look, and bentgrass, a type of fine, ornamental grass that’s quite high-maintenance.

However, “when deciding to seed a lawn, selecting the right plant for the right place is crucial”, said David Hedges-Gower. “This is why prioritising native species over dwarf ryegrasses is recommended, as with a bent fescue lawn, you ideally won’t have to reseed your lawn again.

Your grass choice also depends on the conditions of your garden, including sun, shade, soil type and what kind of lawn you want. For grass seed that’s particularly hardwearing for regular foot traffic, we recommend Sprogs & Dogs (a mix of dwarf ryegrass and creeping red fescue), while The Grass People’s ‘Steadfast Ultra Shade’ mix is cultivated particularly for shaded areas that never see direct sunlight.

What time of year is best to seed a lawn?

You can sow grass seed at any time of the year, but spring (March to May) and early autumn (September to October) will yield the best results. During these periods, the weather will be warm and sunny, but you’ll also take advantage of the likely rain to help germinate the seeds. Conversely, the summer months risk scorching any newly sprouting seeds.

Of course, the UK weather can be temperamental at the best times, so look for a two-week window of consistency: daytime temperatures above 13ºC, night temperatures no lower than 6-7ºC and no threat of frost, storms or torrential rain.

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Is overseeding different to seeding my lawn?

If you plan to sow more grass seed in a pre-existing lawn, this process is called ‘overseeding’, and it works well for patchy and thinning grass. The required steps are similar to seeding from scratch, except you’ll also need to aerate and possibly scarify the soil as part of the prepping process.

Scarifying your lawn

“For existing lawns, it’s necessary to reduce or eliminate existing competition – as in, other grasses”, said David. “This often requires a thorough scarification, and even a lawn mowing ‘scalping’, to remove unwanted organic material and provide a suitable surface for the seed to adhere to.”

Scarification is a more intense type of aeration and, put simply, means ridding your lawn of any thatch or moss build-up, as too much of this will prevent the new grass seed’s root systems from accessing enough water and nutrients.  “Ensuring soil contact is vital, especially if top dressing with soil isn’t done”,  David agreed.

You can manually scarify the lawn with a garden rake. However, this will only pull up thatch and moss from the surface. A dedicated scarifier can penetrate further down to the thatch and moss deeply rooted in the lawn.

Aerating your lawn

Regular aeration of your lawn can significantly improve its health: it allows air to penetrate the soil, reaching grass roots and letting water and nutrients in – plus, it enables excess carbon dioxide to leave the soil.

You can use a garden fork, a rolling aerator, and even spiked aerating sandals to aerate your lawn. It’s not advised to use a fork unless you have a small lawn because the solid spikes can worsen the compaction of the soil. The best aeration comes from using a hollow tine aerator: this removes small plugs of soil with every spiking action.

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How to care for your newly seeded lawn

After seeding, water the area and monitor it for signs of germination, which takes around six weeks. Continue to water regularly until the grass establishes strong roots. Cassie advises against walking on the freshly seeded area until the grass has grown strong enough to withstand foot traffic.

Regular fertilising with the best lawn feed will help keep your lawn healthy once it’s growing. Make sure to use a fertiliser for young lawns, too.