It's necessary to use fertilizer before any problems are obvious. Once disease, weeds or insects are noticeable; the lawn's health has already been seriously compromised. Even without these annoyances, lawns need fertilizer to grow; if they don't get it, blades will turn yellow, thin, and fail to thrive. Grass then becomes susceptible to any number of unattractive and unhealthy conditions. Lawns need fertilizers just as much as humans need food!



Many factors play a part in determining which fertilizer is best. All grass requires more fertilizer during its growing seasons, but some fertilizers should not be used during rainy periods, such as those with a high nitrogen level and no time-release mechanism. If the lawn owner will not be able to keep up his fertilization schedule of every 2 weeks or so due to personal scheduling, that will also determine the kind of fertilizer timing that may be needed. (Slower-acting fertilizers only need to be applied about every 6-8 weeks, but are usually more expensive.) The lawn owner should even consider whether sprayer or spreader application would be most effective for his physical limitations and size of lawn. (It may be confusing to determine the varying amounts needed for liquid instead of granular fertilizers, and using liquid fertilizers with sprayers may be logistically difficult for those with very large lawn areas. But, it does prevent the homeowners from having to store large bags of granular fertilizer and purchase, then store, a spreader.)

Most fertilizers use a mixture of approximately 30% nutrients (stated as a series of 3 numbers on the product bag) and 70% "fillers" or chemical agents. Lawn owners should have an idea of what type of grass his lawn contains and how large the square footage is before purchasing any type of fertilizer. Fertilizer requirement is based on a calculation of one pound of nitrogen per 1,000 square feet of grass for "average" Centipede grass.

The amount of nitrogen chemicals, which encourage the green color, is the first of the first 3 fertilizer numbers on the product bag, such as 29 in the series 29-3-4. To figure out how many bags to buy, divide the first number, 29 by 100; the result is 3.5 pounds for every 1000 square feet of grass. Once the amount to be applied has been reached, application should stop, and any remaining fertilizer stored for future use. This is important to remember, because just as too little fertilizer will keep a lawn from growing into a lush and thick green carpet, too much fertilizer will burn and kill it. (It's also good to remember that applying fertilizer with higher nitrogen levels too frequently can cause grass to grow more quickly and need additional mowing!)

Using the above calculation, some grasses will require more than one pound per 1000 square feet: Buffalo and Blue Gramma may need up to 2 pounds, fine Fescue, Bahia, St. Augustine, Ryegrass, Zoysia should have 2 to 4 pounds, and Bermuda, Kentucky, Bentgrass, and tall Fescue must be given 3 to 6 pounds. (All of these estimates can be based on the lower range for cooler temperature areas and shorter growing seasons.)

Buyers should not be concerned only about the nitrogen amounts. The second number represents phosphorous, which affects growth of the grass roots. The third number reflects the fertilizer's level of potassium, which builds the lawns' resistance to stress. Many experts believe that any nitrogen numbers below 12 don't provide enough nutrients and are not worth their low prices. But, Zoysiagrass, Fescue and Bermudagrass will normally respond well to all fertilizers, so price can be a deciding factor for those varieties.

Regarding organic fertilizers: they may not be high in all of the nutrients that lawns require, and there may be adverse reactions. Cottonseed meal results in acidity, so it's better for certain plants than for grass. Blood meal is so rich in nitrogen, it may cause burning. Fish emulsion has a very strong odor that takes a few days to fade. Manure, although nutritionally balanced (based on what the animal is eating) may be low in all of those nutrients. Plus, manure is most rich in nutrients when fresh (but not too fresh or the high salts will burn roots) and acquiring it may not be always easy for the lawn owner, who probably does not want to apply 70 pounds for every 1000 feet of lawn area!

For optimum results, professional lawn care consultants can recommend specific amounts and blends of nutrients to ensure that the lawn owner gets the most out his fertilizer and lawn enjoyment!