Lawns that have the finest close-cropped finish must be carefully prepared to the proverbial billiard table flatness to achieve this. This doesn't apply to the majority of domestic lawns. A little and often is the real secret, this is far better than letting the grass get very long and then cutting it down. Irregular cutting eventually results in a poorer quality more weed infested lawn. In a hot dry spell, raise the blades a little higher than normal, also do this for the first cut of the year in the spring.
Fertilisers Apply a proprietor lawn fertiliser in late spring when the lawn is growing strongly.
General garden fertilisers can be used and are effective, but one specifically balanced for lawn use is the best. Lawn fertilisers are frequently mixed with weedkillers and should be used following weedkiller application if not. The fertiliser encourages growth of the grass over the bare patches left by dead weeds and makes it more difficult for the weeds to return. If you collect grass cuttings and take them away from the lawn, it is essential to feed the lawn to keep it healthy and weed free. Every time you remove grass cuttings, you are removing nutrients that were in the soil.