The soil provides plants with nutrients that are essential to make them grow. Fertilizers are used when the soil does not have sufficient nutrients. How do you choose a fertilizer? There are two important things to know.
First, what do the three numbers on the label mean, like 5-7-4? This is referred to as the “NPK” ratio and represents the available nutrients by weight in the package. The first number is nitrogen (N), the second is phosphorus (P) and the third is potassium (K). For example, if a 100-pound bag of fertilizer has an N-P-K ratio of 5-7-4, it contains 5 pounds of nitrate, 7 pounds of
phosphate (which contains phosphorus), 4 pounds of potash (which contains potassium) and 84
pounds of filler.
The second thing to know is whether the fertilizer is organic or synthetic. Organic fertilizers are
made naturally from mineral deposits and organic material, such as bone or plant meal or
composted manure. They are not water soluble so they are usually applied in Fall to provide
nutrients for the Spring growth. They also help to improve soil texture, stimulate soil life, or
improve your soil's long-term fertility.
Synthetic fertilizers are manufactured raw materials. They are water-soluble and can be taken up by the plant almost immediately. They can give your plants a quick boost, but do not help to
improve the soil.