How to sow grass seed for brilliant lawn results

A beautiful lawn starts with the smallest seed. By following these steps, you can effectively choose and sow the right grass seed to grow a lush, healthy lawn.

What is the best grass seed?

“The type of grass seed is really important”, explains the ‘Garden Ninja’ Lee Burkhill, award-winning horticulturist and presenter on BBC1’s Garden Rescue. To work out which grass seed you need, you have to consider factors such as:

• local climate
• soil type
• sunlight or shade
• foot traffic and usage
• how you want your lawn to look

Happily, most grass seeds are a mixture of varieties. That means you can find the right balance of looks and toughness for your requirements, whether you’re hoping for a lush lawn, a hard-wearing football pitch or just some improvement in an otherwise patchy mess.

“Any utility lawn mix is fine if your garden is free-draining and sunny,” says Lee Burkhill. But there are a few things to look out for. For example, general all-purpose seeds may lead to a patchy lawn if they don’t contain species like Festuca trachyphylla (hard fescue) or Poa supina (bluegrass) which can stand being in the shade. And, particularly if you have kids or pets, you’ll need a hardwearing ryegrass that can stand up to being trampled (or worse).

Burkhill also advises caution over the amount of work that goes into a perfectly manicured lawn: “Ornamental lawn seeds are saved for people who obsess over their lawns and can give them the weekly maintenance they need, so avoid them unless you want to become a lawn care pro.”

If you’re looking to fix dead or worn patches, Paul Hicks, product manager at STIHL, suggests using a quick-fix repair kit with a blend of seedling soil and grass seed: “Ideally, this would be the same mix used for your lawn in the first place.”

To make sure you choose the right option, check out our guide to the best grass seeds for your garden for more.

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What type of soil do you have?

Your soil conditions will affect the type of seed you need. For a DIY soil test, fill a jam jar and give it a good shake. Then leave it to settle and you can determine the type of soil that you have based on the results. Alternatively, you might ask around to find out what kind of soil you have in your area – ask a local gardener, enquire at your local garden centre or join local communities and Facebook groups to discuss the soil conditions.

Clay soil generally locks in water and is rich in nutrients that plants need. Sandy or stony soils tend to let water drain through, which makes them likely to be drier. Loam soil is a mix of sand, silt and a minimal amount of clay, making it great for grass.

When to sow grass seed

“The best time to sow grass seed is in April, when the weather is better and your soil has warmed up,” says Lee Burkhill. “Sowing any earlier usually reduces the speed of germination as the ground is too cold and wet.”

Burkhill warns to avoid sowing seed in the heat of the summer as keeping the seed moist will be near impossible. If you’ve missed the spring, wait until September and October instead, as planting in the autumn gives seedlings a chance to establish before the cold winter weather kicks in.

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How long does grass seed take to grow?

How long grass seed takes to germinate will depend on the time of year and conditions, but germination typically takes about 1 to 3 weeks. Be patient when watering during this time, and avoid water logging the ground.

How much water does grass seed need?

If you plant in spring, make sure you continue to water through any dry spells. “Grass sown in the spring needs to be watered into summer”, explains Paul Hicks. “The new grass won’t yet have a mature root network which can tap into underground moisture, so you’ll need to provide the water the lawn needs to thrive.”

It’s also important to know when to stop watering grass seed: “Seeds hate being flooded or drenched with ice-cold water straight from the hose”, says Lee Burkhill.

How to plant grass seed

Here’s a step-by-step guide to sowing grass seed:

Prepare the soil

Go over the area where you plan to sow the grass seed and remove any debris, rocks or existing, but unwanted, vegetation. Loosen the soil and aerate to a depth of around 2 to 3 inches using a rake, fork or garden tiller. Not sure how? Read our in-depth article on how to aerate your lawn.

Level the soil

If you can, use a rake to level the soil surface. That will help achieve an even look and you’ll find it easier to push a lawn mower over a flatter garden, with minimal ruts or bumps. We’ve got a full length guide on how to level a lawn if you need advice in doing so.

Feed and fertilise

If your soil lacks nutrients, consider adding a layer of fertiliser or plant food before sowing the grass seed. If you do feed the lawn, choose a fertiliser formulated for new grass seedlings.

Calculate seed amount

A kilo of seed covers an average of 30 square metres, or more if you’re reseeding an existing lawn. Avoid laying too much seed as this overcrowds the soil and can cause bald patches, so don’t feel the need to buy huge amounts.

Sow the seed

Spread the grass seed evenly over the soil using a handheld or mechanical spreader. Start by sowing in one direction and then go perpendicular to your initial path to ensure thorough coverage. Try not to leave any bare spots but, again, avoid over-seeding.

Rake in the seed

After sowing, lightly rake the surface to try to cover the seed with the top layer of the soil.

Lightly fertilise

Lee Burkhill suggests using a sieve to spread some compost over the seed immediately after sowing. “This retains moisture around the seeds and reduces your need to water your lawn seed daily”, he explains. Old spent compost from pots will do the trick.

Plant food and fertiliser are optional but once the grass has been established – after about 6 to 8 weeks – you might consider applying a balanced fertiliser to promote healthy growth.

Water the area

After you’ve sown the seeds, water the area immediately to moisten the soil. Keep watering during the germination period – this typically takes 1 to 3 weeks – but avoid water logging the ground.

“Grass seedlings typically appear around 10 days after sowing”, says Richard Ferguson of Hozelock, “and it’s important to water effectively at this stage to help your new lawn establish. The time of year you sow your grass seed and the level of rainfall will determine how much water the seedlings need, but begin with a daily light water, using a hose or watering can, for the first 6 weeks.”

Ferguson suggests making use of the different settings on your hose spray gun or nozzle as “light watering is key to prevent the seeds from becoming dislodged or overwatered, especially during the spring showers.”

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When should you cut new grass?

You’ve sown and you’ve grown, so the big question now is: when should you mow?
“You want to leave freshly germinated lawn seed for 3-4 weeks before the first cut,” says Lee Burkhill. “Mowing quicker than this can do more harm than good, as the mower may simply rip out the newly seeded grass.”

Don’t charge in and chop it all off in one go. “You should always be patient with a new lawn,” says Paul Hicks. “While the grass is germinating it requires water and rest above all else. I recommend waiting until the grass has reached a height of around 8-10cm before the first cut, as this will promote denser growth.”

Hicks also advises leaving new grass to grow higher than mature grass so the new lawn establishes a healthy root system. “Plants rely on green plant tissue to generate energy via photosynthesis; the more energy they generate, the more vigorous the root growth, whereas consistently mowing your lawn at a low height can reduce overall root mass and depth.”

Set your lawn mower blade higher and cut no more than one-third of the length of your grass at a time. It’s also a good idea to make sure your lawn mower blades are sharp, as a blunt blade can damage new grass. Fortunately, sharpening your lawn mower blade is a job you can do yourself.

When you do mow, there’s no need to collect up the grass cuttings: “To really help your new seeds grow into a lush lawn, mulching is a great option”, says Hicks. “This means cutting the lawn little and often and dropping the tiny clippings back into the lawn to act as a nutrient-rich fertiliser.”