Revitalize Your Lawn: Fertilize
Lawn care do-it-yourselfers can save some serious money by following a few tips from a turf specialist in Penn State's College of Agricultural Sciences.
"Dollar for dollar, fertilization does more to revitalize thin, weedy lawns than any other single management practice," says Peter Landschoot, associate professor of turfgrass science. "With more user-friendly products on the market, lawn fertilization has never been easier -- provided you follow a few basic steps.
"The first step is to take a soil test," Landschoot says. "This will tell you how much fertilizer and lime is needed."
Next, buy fertilizer. Fertilizer should be bought on the basis of its quality, not the size of the bag or the price. Value depends on the amount and source of nutrients in the bag. Fertilizer labels have three numbers that designate the percentages of nitrogen, phosphate and potash in the bag. A 30-3-10 analysis, for example, means that the product contains 30 percent nitrogen, 3 percent phosphate and 10 percent potash. Lawns usually require annual applications of all three of these nutrients, with some lawns needing higher amounts than others. Your soil test report will provide information on which fertilizer is best for your lawn.
Some products contain "slow-release nitrogen" or "water insoluble nitrogen." "It's a good idea to have some slow-release nitrogen fertilizer in the bag," Landschoot says. "This will provide longer lasting green-up and reduce the chance of fertilizer burn. However, if all or most of the product is slow-release nitrogen, green-up of the lawn can be very slow. It may take weeks or even months to occur."
Next, homeowners must buy or rent a spreader, unless they already own one. There are two types of spreaders for lawn fertilization -- rotary and drop types. "Rotary spreaders will do the job faster than drop spreaders since they are equipped with a rotating apparatus that throws the fertilizer out in a wide swath," Landschoot says. "Thus, fewer passes are required to cover the lawn. Drop spreaders typically are more accurate, but since they don't throw the fertilizer, the swath is narrower, and more passes are needed to cover the lawn."
Rotary spreaders are more practical for larger lawns, while drop spreaders are only suitable for small to medium-sized lawns. Many lawn fertilizers now contain spreader settings on the label. The setting, usually a number or letter, controls the amount of fertilizer applied. Look for a fertilizer that lists your spreader type (rotary vs. drop type) and model on the bag, then adjust the setting accordingly.
"When it comes to fertilizer, more is not necessarily better," says Landschoot. "Never exceed the setting listed on the label. Doing so can result in excess growth, which requires more frequent mowing and weakens the turf, making it more susceptible to heat and drought in summer." Too much fertilizer also can dehydrate the grass, resulting in 'fertilizer burn' or dead turf.
To apply, pull or push the lever that closes the openings in the bottom of the spreader, pour in the fertilizer, and adjust the spreader setting. Find a spot on the lawn where you want to begin the application -- typically along the strip of turf nearest to the street or driveway so you can minimize the amount of fertilizer that gets onto pavement. "Always begin walking before you open the spreader," Landschoot says. "This will eliminate burn marks that result when too much fertilizer falls out of the spreader while it is standing still." At the end of the pass, close the spreader openings before you stop walking.
To avoid creating dark and light green stripes in the lawn, ensure that each pass is adequately spaced. With rotary spreaders, space each pass so that a small amount of fertilizer overlaps with fertilizer applied from the previous pass. With a drop spreader, each pass should begin right up against the strip of the previous pass -- like laying strips of wallpaper.
The best method of applying fertilizer is to use the half-rate setting suggested on the fertilizer bag and go over the lawn twice in a crisscross or grid pattern. This will further reduce the chances of striping. Remember, fertilizer does not move once it is on the lawn -- wherever it lands, your lawn will turn green, and where it does not land, it will not turn green.
Landschoot suggests applying fertilizer two or three times per year. Homeowners should fertilize lawns in mid-spring (late April or early May), late summer (around Labor Day), and late fall (around Thanksgiving). If you use late fall applications, you may be able to delay spring applications until late May.
Finally, never apply fertilizer during hot, dry weather in mid-summer. This can damage turf and make it more susceptible to summer diseases. Also, never make applications on frozen ground or on paved surfaces. Fertilizer on hard surfaces can be washed into storm sewers and end up in groundwater. If it lands on the driveway, simply sweep it into the lawn.