In order to understand a fertilizer we need to first understand the components that make up a fertilizer. The numbers always appear in the same order and represent the percentage of N, P, and K in the bag. Plants that are mostly leafy, such as lettuce and grass, need plenty of nitrogen for proper growth. That is why lawn fertilizers always have a high first number in the sequence, which represents higher levels of nitrogen present within the bag. This nutrient promotes strong roots and stems.
Fertilizers now come in many forms, making the choices of what to use even more confusing.
Granular types are applied by using a spreader or by working it into the soil. Water-soluble types, usually powdery in texture and blue in color, are meant to be dissolved in water. Organic types are processed materials such as dried blood, bone meal and manure. Organics have low levels of nutrients compared to the other two, but are the fertilizer of choice with organic growers. Each type of fertilizer has its advantages and disadvantages and the one you choose to use is really a matter of personal preference.