Fertilizing a nutrient-hungry grass lawn is the most important part of its upkeep. Although grass clippings decompose easily into the lawn, providing a small amount of nitrogen application of a store bought fertilizer is essential fro green, dense grass. Too little nitrogen in the lawn, says the University of Minnesota Extension, causes slow growth, reduces root growth and makes the grass intolerant to adverse weather and disease.
Mow the grass so that it is at the correct height. As a general rule of thumb, most grasses require a height between 2.5 and 3 inches in length.
Aerate the lawn using a core aerator to remove plugs of dirt from the lawn and decompose thatch, which may develop in a regularly mowed lawn, says the University of Minnesota. Aeration is the extraction of dirt plugs from the lawn to ease compaction and improve water drainage. Use a core aeration machine or a hand-held core aeration device to remove plugs, aerating in two directions to get the greatest coverage. Rake the plugs of dirt after aerating to break them apart.
Measure your lawn in square feet using a measuring tape. Multiply the length and width of the lawn for the square feet sum.
Buy a complete fertilizer with a ratio around 24-4-16 (6-1-4) to 24-3-6 (8-1-2), suggests the Oregon State University Extension.
Apply 1 lb. of nitrogen per 1,000 square feet. Calculate the weight of the fertilizer bag by the percentage of the nitrogen weight in the bag. A 20 lb. bag of fertilizer, with 24 percent nitrogen in the bag, will have 4.8 lbs. of nitrogen in it (24 x. 24 = 4.8 lbs).
Fill your drop spreader with fertilizer and attach a piece of cardboard bent into the shape of a 'v' to the bottom of the device. The cardboard catches the fertilizer as it falls. Mark off a 100 square foot area of the lawn and walk the fertilizer throughout the area set to the manufacturer setting for your desired rate of application. Weigh the fertilizer that drops into the cardboard after walking the 100 square feet and multiply that number by 10 to get the amount of fertilizer you need for 1000 square feet. This calibrates the spreader.
Set the drop fertilizer to the setting used to calibrate the device and apply half of the fertilizer going north to south and the second half of the fertilizer going east to west for the best coverage, suggests Oregon State University. A drop spreader will, as the name suggests, drops the fertilizer beneath the device. Overlap the application by following the wheel marks from the previous pass for best coverage.