September is traditionally the time for sowing a new lawn, but the ground should be prepared at least a month in advance. Thoroughly dig over or rotavate the area. Remove large stones and all bits of perennial weeds as you go. Consolidate the soil by walking methodically over it on your heels, with short steps - like a duck-waddle. Rake the surface level and allow dormant weed seeds to germinate. Hoe or rake these out periodically. If the soil is poor, rake in some fertiliser about a week before sowing.
Grass seed mixes are graded from 1 to 4: number 1 for the velveteen bowling-green, 2 for your average "nice" lawn, 3 for child and pet-proof swards, and 4 for difficult areas such as dry banks and shade. There is now also a new, hard-wearing, slowgrowing mix that comes under various brand names.
Ideally, sow the seed when the soil is dry on top, but moist underneath. Allow 1 to 1 1/2 ounces per square yard. Rake the surface and scatter half the seed evenly across the plot. Strew the rest at right angles. Rake in lightly. Do not water.