This is a MUST READ for anyone growing tomatoes. There's LOTS of science behind this planting plan that makes super healthy plants. Links give even more advice/ with pictures. remember to read this before planting.
20 Insanely Clever Gardening Tips and Ideas (with pictures!) - Epsom salts in the soil for tomatoes and peppers. Add a Tablespoon or so in the soil when first planting and then sprinkle more into the soil when mature.