A thick green lawn is the crowning jewel of any landscape design, but unfortunately even the most well-maintained lawns can grow tired and sparse over time. Give your lawn the 'spa' treatment of aeration, de-thatching, feeding and watering to revive its vigor, and reseed if necessary to restore its green healthy glow. Keep your lawnmower height raised, mulch your clippings, and treat your lawn regularly with a top-dressing of compost or liquid fish emulsion fertilizer to maintain its revived condition.
Set your lawn mower to cut at about 2 inches high, and mow lawn in September with bagger in place. Use grass clippings from this mowing in compost or for garden mulch.
After mowing, dethatch the lawn by pulling a thatching rake roughly through the grass and removing the dead grass and roots which are entangled in the rake. Work in a grid pattern with the thatching rake, moving first in parallel lines in one direction, then at a second set of parallel paths at right angles to the first set. Rake up the thatch with a lawn rake and place it in wheelbarrow or large plastic tub for removal. Place removed thatch in compost or use for garden mulch.
Aerate the lawn by working across it in parallel-line passes, poking 4-inch deep holes into the soil surface with a spading fork or hand-held lawn aerator, or by rolling over it with a rolling lawn aerator.
Water the lawn lightly, applying a dilute solution of liquid fish emulsion fertilizer with a hose-end sprayer immediately after aeration. Do not saturate the lawn.
Spread a 1/8th inch thick layer of well-aged compost over the lawn, using lawn rake to distribute it evenly.
Spread grass seed over the compost if desired, at one-half the seeding rate recommended by the supplier for over-seeding thin lawn areas, or at the full seeding rate recommended by the supplier in bare patches.
Top the seeded areas with another 1/8th inch of compost, water lightly, then spread a very thin layer of light straw mulch over the seeded areas. Water newly seeded areas daily for one week, then every other day for an additional 10 days.
Rake straw mulch off of lawn in four weeks in warm climates. In zones with cold, snowy winters, you can leave the straw mulch on until spring and either rake it off or simply mow over it with your first lawn mowing to add more organic matter to the soil.
Water your lawn no more than once a week during the subsequent growing season, and set your mower at 3", removing bagger to allow lawn clippings to mulch into the lawn.