A good soil test kit will identify significant nutrient deficiencies of pH problems, and can be a useful benchmark for a long-term soil improvement program. This is the least stable soil nutrient because it leaches out of the soil very quickly. It is also the one you should be most attentive to. Too much nitrogen in the soil will produce lush foliage instead of fruit, and it can burn plant tissues. Organic sources of nitrogen include aged animal manure, dried blood, fish emulsion, bird or bat guano, cottonseed meal, alfalfa meal, cocoa bean or peanut shells, bone meal, hoof and horn meal, feather meal, wood waste, human hair, fish meal or scraps, seafood meal and soybean meal.
Plants use phosphorus to flower, fruit and seed.
Phosphorus promotes strong root growth, makes stems strong and improves disease resistance. Most soils are deficient in phosphorus, and when the soil pH is too high or too low, phosphorus becomes even less available. Phosphorus is not very water-soluble, so it doesn't move through the soil. For best results, it should be incorporated into the root zone where it can be utilized. Microorganisms convert phosphorus into a form that is available to plants, which is why phosphorus deficiencies are often apparent in the spring when soil microbes are not very active.