The extremely hot and long summer has been hard for grass. September is the best month to tackle dead patches of the lawn and take steps to make sure that it comes back gleaming green for the spring.
The first step is to scarify; it's easiest to do this if you can get your hands on a scarifier but if not, a wide rake with wire prongs will do the job. Remove all the dead grass or 'thatch' and any dead leaves. Then concentrate on the bald areas by scratching the surface to loosen the soil. Apply a thick layer of lawn repair mixture on the bare patch, however if you can't find this, sprinkle grass seed generously. Tamp it down firmly and then, using a fine rose on a water can or hose, water in well. Water it every day for about two weeks.
Autumn is also a good time to fertilise the grass as the roots are continuing to develop. Using a dry fertiliser, sprinkle it over the whole lawn area. Quantities should be stated in the instructions on the packet.