There are several ways to maximize the use of fertilizer. This generally involves finding out what fertilizer is most needed, when to apply it, and how to apply it. To find out what kind of fertilizer is best, a soil test must be performed. The best time to apply the fertilizer depends on the plant that is being fertilized. It is also important to know how to apply fertilizer in order to avoid over-application that can ruin the plants or lead to excessive run-off that can potentially contaminate nearby ground water.
It is generally recommended to get a soil test done every three to four years. This test should be done three to four months before the application of fertilizer. The gardener or farmer collects soil from the place he or she plans to apply the extra nutrients and sends this sample to a local lab that performs soil tests. While the results are often sent back quickly, a delayed response should be expected if the sample is sent around the time local farmers begin to fertilize their fields.
Using fertilizer is not as simple as asking a sales associate what mix is best for a certain plant. A person can learn to read fertilizer labels — which vary by country — and be able to decide which fertilizer is best. Often, the label reads something like 10-10-10, with each number representing the amount of an element in the mix. For example, in the United States, the labeling is arranged to read nitrogen, phosphorus, and potassium. Once the soil test results come back, the person will know what mixture to purchase and how to read the fertilizer labels to find this mixture.
To best distribute the fertilizer over grass or seeds, many people use a fertilizer spreader. Using fertilizer with a spreader helps to evenly distribute fertilizer without under- or over-fertilizing the plants. There are a lot of inexpensive fertilizer spreaders meant for people wanting to upkeep their lawn or tend a small garden, but the commercial ones designed to spread fertilizer on large fields cost much more.
The nutrients in fertilizers can be a health hazard if they reach and contaminate water sources. It is important to follow safety instructions when using fertilizer and not over-fertilize. This minimizes the risk of polluting lakes, rivers, or oceans. Not only is fertilizer-polluted water potentially dangerous to humans, but the nutrients in fertilizer cause algae to grow more rapidly, which in turn depletes the water of oxygen. Many underwater plants and animals cannot live with little to no oxygen in the water.
