To increase the size of onions, garlic, tulips and iris, or any type of bulbs, apply a sufficient amount of sulfur based on an accurate soil analysis. Conversely, too much sulfur is antagonistic to phosphate performance. The relationship between sulfate and phosphate availability in the soil helps demonstrate the principle that all elements need to be sufficiently in balance.
Calcium
Gypsum, whether in pellet or powdered form, has its place. What most never realize is that using even small amounts of gypsum on soils that are severely calcium deficient will soften the soil initially, yet ultimately cause it to become increasingly harder -- how fast depends on the amount used. The calcium present determines the porosity of the soil, and until a soil is saturated with at least 60% calcium the pore space is not sufficiently large enough for other cations such as sodium, magnesium and potassium to be leached out. In calcium deficient soils, if that soil has no compaction layers, as sulfur moves through, only calcium will be stripped and carried away, leaving magnesium, which the leached calcium has been controlling, to be released to take its place. A good rule of thumb is that for every percent calcium drops in a soil, magnesium will increase by that percentage. Both provide a one for one exchange percentage-wise. Furthermore, depending on the amount of sulfur and phosphate in each soil, gypsum can have a beneficial or an adverse effect. If soils are low in phosphate, adding inordinate amounts of sulfur can adversely affect the availability of the phosphate. This is also true in the reverse in that use of too much P can adversely affect S availability.
A three volume set of Mittlieder's international work on nutrients for vegetable gardens gets frequent use as an authoritative reference as we work with gardens and vegetable production around the world. His work in showing severe nutrient deficiencies of various vegetables is very useful. But bear in mind that his methods were developed to help very poor soils in Third World countries to help their peoples grow their own food. The value of his approach for me was that of solving evident problems.
Too much zinc will tie up phosphate just as too much phosphate will tie up zinc availability. When copper levels in soil are higher than zinc, it can also cause a zinc deficiency in the crops. If manganese is added when iron availability is lacking, all it takes is 1 ppm more Mn than Fe to be available in the soil and the iron begins to be oxidized by the manganese in the leaf of the plant. These problems can be identified only by proper soil tests. The newer 10 minute quick test for trace elements that most labs now use will not give proper measurements because, when plant parts are ashed in order to do a tissue analysis, the oxidized iron shown as available iron is not in fact available. Plants can be severely chlorotic, easily recognizable as iron deficient, but using tissue testing will not reveal it to be an iron problem.
These are just a few of the problems that can occur without a soil analysis to show the way. If you can see any deficiency like those Mittleider points out time and again in his reference works, then use the materials he recommends at the rate he recommends to solve the problem, but do not keep pouring it on. Use soil testing you can rely on to tell you whether there is too little, just enough, or too much of any given element. A lack of micronutrients affects the crops long before it can be seen in the leaves. But in the absence of proper measurement the chances are the problem will not be correctly identified and solved at such an early stage.
In summary, for freshness and food value alone, growing and consuming what is organically grown can be worth the effort. Still, whether growing or consuming organically grown foods, without proper testing of the nutritive values of the crops being grown they can fall far short of what they should be in terms of most beneficial nutrition. Far more effort needs to go into assurance that the organic food supply is based on the production of nutrient-dense foods. Those who grow organic foods should be able to demonstrate that they are not just “organic by default” -- meaning the grower has simply stopped using poison sprays and commercial fertilizer and assumes the harvest will then provide a decent source of food.
The same is true for organic fruits and vegetables. Hence comes the proof of the value of growing your own foods, regularly testing the soils in which they are grown, ensuring that all the necessary nutrients are present and the biological organisms healthy soils require are properly fed, and knowing that what you put on your plate and consume meets the high standards for good health. When that is done, the real worth of investing time and labor to grow your own top quality produce becomes its own reward.