Renovating a Neglected Lawn
Begin the process by examining the grass and weeds covering the lawn. If the dominant plants are coarse grasses, mosses, and persistent weeds, the best solution is to lay a new lawn. If, however, good-quality grasses make up the main part of the lawn, they can be made to re-colonize the whole lawn area.

Start renovating in spring before the grass begins to grow actively. Cut down tall grass and weeds to 2 in. (5 cm) above the ground. Use a rotary lawn mower, a string trimmer, or a pair of shears, depending on the height of the growth.

Remove all dead vegetation, using a rake or blower, and move large sticks and stones. Mow the grass with the lawn mower blades set as high as possible. Subsequent mowings should be carried out regularly, with the blades set highest in summer. Remove the clippings or leave them in place (which reduces the need to fertilize).

Fertilize the lawn in late spring or summer, using a general lawn fertilizer first. Then apply a selective herbicide about 2 weeks later. Some manufacturers supply a mix of fertilizer and herbicide that does the job more quickly and easily. If a test indicates that soil pH is much below 6.8, apply lime in the amounts recommended by the testing kit or report - lime will also help to rid the lawn of moss. Place the lime in a fertilizer spreader or sprinkle it by hand over the affected area. If, after 6 weeks, some persistent weeds remain, use a selective liquid herbicide containing mecoprop.

In fall, apply a fertilizer rich in slow-release nitrogen, and a fungicide, if needed. (These may be available in a combined form.) Remove coarse grass with a selective application of glyphosate.

A week or two later, aerate the surface all over with a sod coring aerator to improve drainage and aeration. Apply a good topdressing of screened soil and sand, or scatter composted manure, garden compost, or leaf mold over the surface at a rate of about 10 handfuls per sq yd/m. Work it well into the surface with the back of a rake.

If the lawn is thin, mix in grass seed with the topdressing at a rate of ½ oz per sq yd (15 g per sq m). Rake off fallen leaves, which can shade young grass seedlings.

Reseed or re-sod any bare patches that appear after the herbicide applications have taken effect. The lawn should be in a satisfactory condition by the following spring, when you can resume normal lawn maintenance.