Hi I'm Tricia, an organic gardener. I grow organically for a healthy and safe food supply, for a clean and sustainable environment, for an enjoyable and rewarding experience. Most gardeners compare NPK numbers diligently to make sure that their plants get the right nutrients but that's only half the story. Plants need at least sixteen different elements for proper growth, the first three elements your plants need are carbon, hydrogen and oxygen plants get these three from the air and water the next six are called the macro nutrients the primary macro nutrients are nitrogen for vegetative growth phosphorus for root and flower development and potassium for vigor. For more information on these macro nutrients checkout our how to fertilize organically video and there are lesser talked about macro nutrients that are important: sulfur, magnesium and calcium. Calcium is an important element to build strong cell walls, magnesium is a necessary mineral for chlorophyll production and sulfur is needed by plants for protein building. The remaining seven are called micro nutrients or trace minerals because they're needed in smaller amounts. The seven trace minerals are boron, chlorine, copper, iron, manganese, molybdenum and zinc. Before you start amending for micro nutrients it's important that you get a soil test. The uptake of micro nutrients is affected by pH and the presence of other elements, for example you might have plenty of calcium in your soil but if you have too much magnesium the calcium you have may not be available to your plants. Let's talk about what the secondary macro nutrients in the trace minerals do and organic sources available. If you're soil is lacking in calcium some great amendments include limestone, gypsum, oyster shell and calcium25. One of the problems that a lack of calcium can cause is blossom end rot in tomatoes pay attention to the affects that these amendments will have on your pH for example= oyster shell lime will raise the pH and the gypsum will lower your pH so make sure that you know what the pH of your soil is before choosing a calcium source. For a magnesium boost use Kmag, dolomite and Azomite. Magnesium is often found with calcium like in dolomite or with potassium like in Kmag the older leaves of plants that need magnesium will turn yellow from edges of the leaf in, careful because there are other deficiencies and viruses that look similar. Straight sulfur can be added using the EB Stone or the Tiger Organic products or it can piggy back with other nutrients like it does with this iron sulfate or gypsum. When sulfur is low the young leaves of the plant will turn yellow, sometimes the leaves will be small and stunted looking as well, micronutrients are only needed in small amounts but not having them can really cause problems for your plants but too much micronutrients is also a problem. Think of micro nutrients as vitamins for your plants. So my favorite plant multivitamins are kelp meal, Gaia green glacial rock dust and azomite and these three are all slow release for a fast response I like the organic liquid kelp. Take care of your babies, give them all the nutrition they need and grow organic for life!