There really is no 'best fertilizer' for growing plants in the landscape/garden. The reason is simple - an overabundance of a nutrient can be as limiting as a deficiency. Unless you know with certainty what the soil requires by way of testing, whatever fertilizer any grower decides on is just a guess. Part of the nutritional supplementation puzzle is making sure the ratio of say N to P is appropriate. If your soil is high in P (and most are), applying a "bloom booster" fertilizer, even if it's someone's favorite, has only the potential to be limiting. If for example, a tomato patch is on soil low in CU or Zn, and fish emulsion has no Cu or Zn, continuation of its use would constitute a perpetuation of the deficiency and result in sub optimum growth.
An excess of one or more nutrients cannot 'make up' for a deficiency of another or other nutrients or a poor cultural condition. This is the premise that underlies Liebig's Law of the Minimum which states,
the growth of plants is not dictated by the sum of nutritional availability, but by the greatest scarcity among all nutrients essential to normal growth. Mother Nature is always going to side with the hidden flaw, so even if all but one nutrient is present and available at the perfect ratio, it's that one pesky deficiency that determines the degree of success; and, it follows that the nutrient available in the most excess will also be similarly limiting. Plant's need Na (sodium) for normal growth, but they need it in such small amounts that the line between deficiency and toxicity is but a hair's breadth.
I've given a great deal of thought to what the goal of nutritional supplementation might look like. I came up with the thought we should strive to ensure all nutrients plants normally assimilate from the soil are A) IN the soil and available for uptake at all times, B) in the soil in a favorable ratio - that is to say in a ratio that closely mimics the ratio at which the plant actually uses the nutrient, C) at a concentration high enough to ensure no nutritional deficiencies, yet still low enough to ensure the plant's ability to take up water, and the nutrients dissolved in that water won't be impeded (by a high concentration of solubles in the soil solution).
Al
