Organic can be tough sometimes but well worth it once you're dialed in. To do it right, there's a little more to it than most people think.
There's a few soil recipes on here and other forums that claim you can do a complete run with them with no additional fertilizers. Either myself or others that I know have tried most of them and we've all found that although they work pretty well in large containers, most don't perform as well in small ones. If you're using small containers, be prepared to add additional fertilizers somewhere along the way in 12/12. Remember though, a good many organic fertilizers ingredients aren't immediately available for plant uptake. You'll have to anticipate the plant's needs and fertilize accordingly.
Read the labels and know what you have before using it. Some people buy expensive fertilizers, but you don't have to. Personally, I use Espoma organic fertilizer w/microbes. Tomato Tone to be exact. Everything they make is good shit though. Anyways, I add some to the soil when I switch into 12/12 (just the one time) and I'm usually good to go for the rest of flowering.
And YES, I use molasses in my organic grows. My soil loves it.