Get Your Dirt Right
The most important elements in your soil for plant growth are nitrogen, phosphorous and potassium. They are the N-P-K you see on fertilizer bags. Plants also require micronutrients such as calcium, sulfur, magnesium, iron, zinc, copper and boron.
Building or improving your soil is extremely important for plant health. The foundation of soil is weathered rock. The best way to build up your soil, after determining what it is missing, is to use natural rock powders.
When I start a new garden, I like to use ground rock phosphate to increase phosphorous levels, if necessary. This enables phosphorous to be released slowly over many years. Adding greensand mined from petrified seaweed deposits, also known as glauconite, increases potassium levels. In addition to potassium, greensand also contains a variety of trace elements known as micronutrients. They are only needed in small amounts for plant health.
To determine what your soil needs, you need a soil test. (See the University of Maryland Cooperative Center’s instructions: http://extension.umd.edu/hgic/topics/soil-testing.)
With test results in hand, you will want to adjust your pH between 6.0 and 6.5 for vegetable gardening. Using dolomitic lime also adds magnesium in addition to calcium. It takes five pounds of lime per 100 square feet to raise the pH one point. A soil test will tell you how much to use. You can lower the pH by adding sulfur.