Patchy or thin grass can ruin the look of your lawn, but it is a much bigger problem than mere aesthetics. Thin grass is susceptible to disease and soil erosion. There is no need to start your entire lawn over if it is slightly patchy. Overseeding, a common practice during fall, is a method of adding grass seed to an existing lawn to make it flush. A winter grass seed is added to the lawn to protect the summer grass from the cold.
Run a core aerator over the lawn during summer. An aerator removes chunks of soil from the dirt, increasing water penetration and removing dead plant material called "thatch" from the lawn. Run the aerator in two directions over the lawn, crossing to two directions for good coverage.
Set your grass spreader for 5.44 to 6.8 Kilogram of seed per 1,000 square feet. Use perennial ryegrass.
Walk the grass seed spreader over the lawn, spreading half the seed in one direction, and the other half in the opposite direction.
Apply a topcoat of manure over the entire lawn, spreading the manure with a rake. Spread the manure so it is a 1/4 inch thick. Water the manure so it is moist but not soaking wet.
Water the turf three times daily---once in the morning, once at noon and once in the early afternoon---providing enough water with each watering to keep the top 1/2 inch of soil moist.
Mow the grass once it reaches 1 3/4 inches in height. Cut it to a height of 1 1/2 inches. Decrease the irrigation after the first mowing to twice-a-day waterings, providing moisture for the top 3/8 inch to 1/2 inch of soil.