I don't mean to be rude, but sometimes if you use your own excrements, you can get better results than with any nutritions.
Animal - plant exchange has always been the best choice in here, no problems so far. If you mix the fertilizer (whatever excrement) with water apx 1:5 (or in resting period 1:15), you can't really over fertilize the soil.
And if you don't have any animals nearby, just don't flush the toilet once.