A lawn grown from grass seed will take longer to establish than one formed by laying turves, but will cheaper and can offer a wider choice of types of grass. The preparation for a sown lawn will probably take longer than when laying turves.
Grass seed should be sown either in spring or autumn. In southern UK, autumn is slightly more preferred while in Northern UK, spring. Whatever time is chosen, the soil needs to be damp and the weather outlook not too hot or dry, nor heavy rain forecast.
Types of grass seed
A number of different mixes of grass seed are available, each has its own particular characteristics and suits specific uses. The name of the mixes may vary depending upon the supplier, and the actual mixes may vary depending on both the supplier and the geographical location.
A reputable, local supplier should be able to advise on the mix to meet any particular need and will often sell the seed loose so that you can by the exact amount required.
Different varieties of seed have a different covering capacity, usually ranging from 1 oz per square yard to 2 oz per square yard (35 to 70g per square metre) - take advice from your supplier as to the particular seed you choose.
The common seed mixes are:
Planning the lawn
Before you start sowing your lawn, give some thought as to what you want, as the lawn will be with you for years to come. Do you want a square lawn or a shaped one? Do you want flower beds in the lawn? With lawns produced from seed, it is worth putting down a full lawn and cutting flower beds into it later when you have lived with it for a year or two.
A lawn need not be flat but you'll probably want to avoid very steep slopes. If you need to flatten an area, remember not to mix top soil and sub soil. Although it may seem a lot more work, the proper way is to remove the top soil from all the area to be levelled, then flatten the surface by redistributing the sub soil, and then replace the top soil over the whole area. Try to build up as much ground as you level down, this will mean that you won't have much soil to dispose of. If the ground is levelled up by more that about a foot (30 cm), leave it to settle for a year before laying turf.
Preparing the site
The lawn area needs to be well drained. If the area suffers from water retention, it may be necessary to lay a soak away or drainage pipes. If a lawn is to be laid around a newly built house, you can expect the builders to have buried some building waste and also to have mixed top and soil soils. If there is any builders sand left, do not dig it in - you need 'sharp sand' to condition soil not 'builders sand'. Start by removing all large stones, blocks and any obviously non-organic rubbish from the surface.
A lawn grows best on well drained medium loam, if your soil is like this, your preparation can be minimal, but if the soil is clay or sandy, you'll need to do more work.
With heavy clay soils, you should add sharp sand, well decomposed manure, compost or rotted leaves. This will improve drainage under the lawn.
With sandy soils, you should add well decomposed manure, compost or rotted leaves. This will improve moisture retention under the lawn.
The top soil needs to be prepared to give a fine, workable soil to a depth of 4 to 5 inches (10 to 12 cm) - if you are adding organic material, you should aim for a minimum depth of 6 inches (15 cm). If the area of the lawn is fairly small, it can be prepared by hand using a spade. For larger areas it is worth using a rotavator - borrowing or hiring one if necessary.
When starting to prepare the soil, it needs to be not too dry and not too wet. Start by digging or rotavating the whole area to the required depth, breaking down any large clumps of soil and remove any stones or rubbish that you see. When digging, work backwards so you don't tread down the soil you've just broken up.
Having turned over the whole area and broken down the soil, add half of anything you need to dig in, and dig over or rotavate the whole area again. Add the other material to be dug in, and again go over the whole area.
Rake over the area to level it, removing any vegetation and stones/rubbish which appears.
Leave the area to settle for a week.
If a lot of weeds or vegetation appear in the week, consider using a non-residual herbicide to kill them off. Carefully follow the instructions and leave the soil for the recommended period before proceeding.
Rake over the area again and remove any more vegetation and stones/rubbish which appears.
Tread down the entire area - starting are one corner, walk slowly across the area placing one foot in front of the other, when you reach the other end, turn around and repeat until the whole area has been trod down (if the area is large, get help from your family and friends - I've not heard of a 'lawn walking party' but there's no reason not to have one!). The first time you do this, you'll probably find some humps and dips, remove these by giving the surface a light racking and repeat the treading down.
Sowing the lawn
Sow the lawn on a wind free day, just before you start sowing, give the area a final raking.
Divide the quantity of seeds into two, (it is better to sow two lighter sowings rather than one heavier). If the area to be sown is large, you can divide the seeds further, this will reduce the chances of covering three quarters of the area and finding that all the seed has gone.
Sow one covering of seeds while walking in one direction, and the second sowing while walking at right-angles to the first covering.
Lightly rake the seed into the top of the soil, you won't cover all the seed but try to cover about half.
Grass seed should germinate and show within 7 to 21 days depending upon the weather, do not walk on it during this period.
If a dry period occurs in this period, use a gentle watering technique (a garden sprinkler or hose with a fine spray attachment pointed skywards) to keep the top of the soil moist. Too mach water applied in the early days can float the individual seeds into concentrations.
If possible, protect the area from birds and domestic pets, chicken wire is ideal but probably impractical except for small areas. On larger areas, tin foil attached to string stretched across the area may help.
When the grass is about 1 inch (2.5 cm) high, gently roll the area with a light garden roller. Alternatively, if you have a cylinder mower, set the blades as high as possible and use this. Or carefully tread the area in the same way as was done before the grass seed was sown.
Leave mowing the grass until it is about 3 inches (7.5 cm) high and then lightly mow with the cutter set to about 2 inch (5 cm). If not using a cylinder mower, lightly roll (or tread) the area after the lawn has been cut.
Reduce the cutting height with each subsequent mowing (and roll after each mowing) but don't cut lower than 1 inch (2.5 cm) during the first season.
Keep playing children and pets off the lawn for the first season, seedlings are delicate plants and need time to become established.