How to Sow Grass Seed

How to Sow Grass Seed

Apart from warmth you need three things when seeding a lawn:

  • Good seed to soil contact
  • Even distribution of seed
  • Constant moisture

*Warmth means an average soil temperature of 10 degrees or above

Please read all sections before putting your seed down. More advice in Lawn Problems.

Good Soil Contact

Start by raking the surface to open it up ready for seeding. Next put in the seed and then gently drag the rake over the surface to start mixing the seed with the soil. Finally, use a light roller; perhaps a half filled water roller or your lawn mower roller and roll the lawn in two directions.

Even Distribution

You can broadcast seed by hand or with your fertiliser spreader; the bag seeder in our store is excellent for grass seed. A shutter one third to one half open should do nicely. Professionals will split the seed into two lots and seed in one direction with one lot and reverse the direction for the second lot. This ensures an even distribution. I suggest you do yours in four lots and seed in four different directions.

Before you begin remove any spare seed you ordered and take a bit extra out as well. When seeding a lawn it is best to be careful at the edges as you don’t want to waste seed on the patio or driveway and conversely you don’t want to grow grass in the flower beds. By keeping a bit extra back you can do a final hand spread carefully on the last 30cm of lawn up to the edges.

If you haven’t already done so now is the time to add a pre-seeding or starter fertiliser

Constant Moisture

Now all you have to do is stop it drying out. This means light watering with a very fine spray, once or twice a day for the first two weeks. If the weather is warm and dry the frequency may need to be increased. Large droplets or heavy watering will move or puddle the seed destroying the even distribution so light frequent watering is required. The golden rule is - don't let the seed dry out.

Watering can be quite a problem so consider watering heavily for a day or so before seeding to build a reservoir of moisture within the soil. Then leave it for 12 - 24 hours for the surface to dry allowing you to walk on and seed the area. If I think watering might be a problem I will cover the area once the seed is down with light polythene weighed down at the edges with bricks. This helps incubate the seeds in cool conditions and prevents moisture loss in dry conditions. Once the seedlings reach an inch or more the polythene can be removed. Once removed you'll need to water as below. Large polythene sheets can be purchased very cheaply from most builders merchants.

The second two weeks should be once a day or every other day. If things start drying out increase the frequency. In month two you can water more heavily and less frequently; perhaps twice a week will do. Finally, water once a week in month three and keep watering if things get dry. New grass is prone to drying in the first six months. Being able to do your seeding in wetter spring or autumn months helps but if you can supply the water or the polythene then summer seeding can be extremely successful.


Depending on the seed used and the temperature you should start to see some green shoots within 10 to 14 days. When the grass hits 5cm (21/2”) you can start mowing your new lawn. Make sure the grass is dry and the mower freshly sharpened. Go slowly for the first few times you mow to ensure the grass is cut as cleanly as possible. Mow on the highest setting possible so that no more than 2cm or ¾” is removed. In addition, the grass will be quite tender so make big slow or 3 point turns.

Once the grass gets its fourth cut you can start bringing the mowing height down over the next 4 to 5 cuts to the desired height for that time of year. If this height is going to be less than ¾” or 2cm then ensure adequate moisture is available otherwise stay at or above 2cm for the first 6 months.


Different seed establishes at different rates with rye grass being the fastest at about 8 weeks. This means you can start using it then but keep the use light for at least another month or two. Other grasses may take 10 to 12 weeks and will take slightly longer to bring into full normal use.

Weed Control

Quite often you’ll find a right old crop of weeds coming up with your lovely new grass for two main reasons. Firstly, virgin soil is a target for every airborne seed in the neighbourhood and secondly, by disturbing the soil you will bring dormant seeds to the surface. Don't obsess too much as most will not survive your first few mowings but those that do will need to be controlled. You can dig or even pull individual weeds out quite easily but do press down on the surrounding soil to prevent grass plants coming up as well. Treating the lawn with a weed killer may well be required but not all weed killers are suitable for new lawns so check out the Resolva and Verdone Weed Killer page for safe use.

Feeding and Lawn Care

Start a normal seasonal feeding regime after about 3 months remembering that the lawn is still young and tender so ensure optimal ground moisture conditions.

You should not use liquid fertiliser or ferrous sulphate until the lawn is 6 months old and you shouldn't be doing any aerating or scarifying in the first year. A full lawn maintenance programme can and should be done in the second year.

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