Super A wrote: 3. Do a soil test. That's the only way to be sure what your garden soil needs. Most states offer basic fertility, & pH soil tests for free. (pH is important, if you're too acid or alkaline, the plants can't uptake the nutrients properly no matter how much you apply.) Go to the extension office, get the materials, follow the directions, and know for sure.
Whatever you buy, before it's time to plant don't forget #3 from my earlier post! In the long run it'll save you time, and $!