Pam, I was using the Vigoro Organic mix, but haven't seen it recently. It has a high coir content, which I do like. Sent my DH for potting soil and he came home with Miracle Gro (not the moisture control kind, thankfully) so we're going to see how that works. I added some extra Perlite and about a cup of alfalfa pellets to each box. The pepper plants are the best they've ever been!
Last year I stocked up on Earth Box Co's replanting kits so I had a supply of their fertilizer and dolomite, plus new plastic covers as well. If you are on their e-mail list, they put a lot of stuff on 40% off once a year which makes it comparable in price to other fert and dolomite. It's also convenient for me to send to my kids for their Earth Boxes, as well. Neither they, nor their spouses are gardeners so expecting them to buy that stuff and measure it out is above and beyond. I have to do it. So I send them each two replant kits and they are sitting there waiting for me when I go to visit in the springtime.