Garden & Outdoor

How to Sow Grass Seed

If you’re planning to sow grass seed on your lawn, starting from scratch with a new lawn can sometimes be the best option for a bigger garden. So if you find yourself in that situation, you’ll need to buy some fresh turf. For others, filling in bald patches or starting a new area can be more than enough. However, achieving the perfect lawn can take some time – as well as requiring good preparation. So you’ll need to know how to sow grass seed and how to choose the right seed.

If you need to know more about how to fix bald patches in your lawn, check out our ‘How to repair patches in your lawn‘ blog.

Before you begin, it’s important to keep yourself and others safe. Always make sure you follow the instructions on your materials and tools, and wear the appropriate safety gear.


Let’s start with what you’ll need.

  1. Choosing the right lawn seed for your lifestyle

    If the grass always seems greener next door that’s probably because they have a different grass variety to your own.

    Choosing grass seed can seem confusing, so start by considering how you plan to use your lawn. Then factor in the basic conditions of your garden and you’re ready to select your seed with confidence.

    • Everyday lawn: If you need hardwearing grass for recreational use then choose a lawn seed mix with added ryegrass. This is ideal for lawns where children play, dogs run, etc. It is resilient and will give you good colour all year round.
    • Picture lawn: For a top-quality finish on a picture lawn, choose a premium lawn grass seed mix. This offers a blend of the best varieties of the UK’s natural grasses. It will require higher maintenance but will look superb if treated gently.
    • Shady lawn: If your lawn is in shade for much of the day, a special shady lawn grass mixture is ideal. These mixes are carefully chosen as they can survive in difficult areas. Although they are very hardy, you will still have to give your lawn care and attention.
  2. Check out your seed bed

    Getting your grass seed to germinate properly depends a lot on the soil you’re working with – so it’s worth having a good look at your seed bed before starting. Ideally, your seed bed should be:

    • Weed-free
    • Level
    • Well-draining

    If not, then you can plan to tackle it while sowing your lawn. Additionally, it’s worth taking a second to think about where your lawn or grass seed will be going. If there are obstacles in the way, move them. If it’s going to get a lot of traffic, consider putting in some stepping stones or walkways to help your grass last longer.

  3. The best time to sow

    If you’re wondering when to sow grass seed, spring and autumn are the best seasons. To achieve some great results, you will need to do a bit of planning. 

  4. Find out how much seed you need

    Measure out the proposed lawn area. The easiest way is to work out a one-metre space and then walk the area – e.g. 10m x10m = 100m2. 

    Sowing application rates are mostly 35 grams of seed per square metre but check the packaging for details. It is better to buy too much rather than too little; you can always use the surplus to reseed any thin patches next season. 

  5. Prepare the soil

    Dig over the soil (the top 2-4 inches) to break down any compaction and help to increase beneficial bacterial levels.  

    Remove stones, weeds and roots as you go along. You can add some soil conditioner to improve  it and encourage a thicker, greener lawn. If your soil has too much clay you can also mix in some fresh soil.  

    Now you need to level the surface of the soil using a rake to help create an even surface. It is not essential to create a dead flat area at this time, as any small irregularities can be smoothed with a top dressing once the grass has established. 

  6. Remove newly-germinated weeds

    If you leave the site for a few days, any remaining dormant weed seeds (and there will be some) will have time to germinate. 

    Once they do, you can kill them off with a weed killer. A glyphosate-based herbicide will work within hours, killing off the new weed seedlings.  

    Removing all the weeds means that the grass seedlings won’t have to compete for nutrition and space. Leave the soil for 7-10 days after using glyphosate and then apply a high phosphate fertiliser to the surface of the soil.

  7. Sow the seeds

    Aim to scatter 35g per square metre (35g = a large handful).  

    Sow half the seed from left to right and the rest from top to bottom to achieve an even coverage. If you want to be more measured, you can always make a rudimentary seed grid by tying four metre-long bamboo canes together to make a square. 

    Then you can lay it gently on the soil as you go, to see how densely covered each patch is with seed. Once you’re finished, gently rake the seed into the soil. Not all the seeds need to be covered as rainfall or watering will ensure the seeds make soil contact.

  8. Keep the soil moist

    It may be a good time to invest in a sprinkler or a hand-held hose attachment – especially if the weather is dry. Keeping the soil moist is needed to encourage good seed germination.  

    However, it is important to water in the correct way. Seedlings need to be kept moist, so water lightly but more often rather than letting the ground dry out and then flooding the area. The best time to water the grass seed is in the evening or early morning. This avoids the harsh midday sun which can scorch and damage newly emerging, moist seedlings. 

    Top tip: A new lawn can be easily damaged, so it’s more important than ever to stay off the grass while it’s starting to germinate. Keep family and pets away from the area  – and if you need to stop birds and wild animals, you can cover with fine wire mesh suspended a few inches off the ground. 

  9. Look after new seedlings

    Germination will happen quickly, the exact rate depending on the temperature and prevailing moisture. 

    Continue to lightly water during the early stages of germination (young plants will require more water than normal). 

    Top tip: Feed a week or two after the initial germination using a high phosphate feed. This will ensure new plants have plenty of the right type of food. Water the fertiliser well.

  10. Trim the new grass

    Watching the young shoots spring up is exciting, and you will soon think about mowing. 

    Keep an eye on the length of the grass and when it gets to around 5-8cm long, trim the grass back just a little to 4cm. New grass plants are fragile and do not have strong root systems, so mow carefully and make sure you use very sharp blades for the first few months. When the new grass is about 4-8 weeks old you can begin to take the mower down to your regular cutting height.

  11. Watch out for more weeds

    Hopefully you will have killed plenty of weeds before sowing your seeds, but quite often you’ll find fresh weeds growing up amongst your new grass.  

    If this happens, you will need to treat when with a new lawn-friendly weed killer.

    That’s your grass seed sown and completed. 

    Don’t forget to upload an image of your new lawn to social media and tag us @Homebase_uk



Writer and expert