How to Sow a New Lawn
If you are replacing an old lawn the quickest method is to kill off the existing grass (and weeds). Use a glyphosate based weed killer, such as Resolva 24H, this will enable you to sow as soon as the old grass has died off. Alternatively skim off the top layer of grass and the immediate soil below and stack it up in a corner of the garden to break down into loam.
Dig over the whole area, removing large stones, roots and other debris. If the topsoil is shallow or poor, add more Top Soil to improve it. Sandy soils should be improved using Soil Conditioner. Be aware when adding partly composted organic matter to the soil that it will break down and could lead to hollows forming.
Rake the area to break up soil clumps and level the site. Getting the level right is critical. Place something with a straight edge over the area, a ladder is ideal, weigh it down at both ends and trail it over the surface. Firm gently and then rake lightly to create a fine see bed. If possible allow the area to rest for a week, hoe off any new weed seedlings that appear.
Mark out the area in square meters using canes. Sow the lawn seed at a rate of 33g/m2 over the top. For more even coverage scatter half of the lawn seed evenly over the area in one direction and then move round 90 degrees and scatter the other half at right angles to ensure good coverage. Repeat this for every square metre.
Keep off the area and protect the seed from birds. Keep the soil moist to aid germination. If there's no rain within a few days of sowing then water the area gently but thoroughly. Continue to water in dry spells.
Distribute the lawn seed evenly, whatever the shape of the area being sown.