Laying turf brings near immediate results when creating a new lawn, but if you are prepared to wait a few months for a usuable, sowing a lawn from seed is cheaper and far less labour intensive. Even a large area can be covered in seed in a matter of minutes.
September is a good time to sow a new lawn, soils are still warm, aiding germination, and autumn rain will do the bulk of watering for you as the seedlings establish.
To prepare the sowing area, dig over the top 20cm of soil and rake over to break up clumps and create a level surface. Tread over the whole area to firm down then, rake again to create a fluffy seed bed; on poor soils also add a thin layer of top soil to work into the surface.
Lawn seed sowing rates are given as grams per square metre. On small areas, divide the space into a grid of 1m squares with string or bamboo canes. Weight out the required seed, and sow evenly across each square – If using Westland Surestart Multipurpose Lawn Seed this will be 33g/m2.
To sow a large area, invest in a lawn spreader. Calibration can be a little tricky, I prefer to lay a test square as described above to get a feel for the required coverage then match this across the area by eye, using the spreader to make parallel runs, with as little overlap as possible.
If using Surestart, seed should start to germinate in days and the area should start to look green by day 10. Only mow once the seedling grass is 6cm tall and only remove 1cm of growth. Only reduce this in late spring, and keep off the grass as much as possible until then.