if im not mistaken, rain water has a lot of nitrogen in it, if you live in a place where you get clean rain water, and not acid rain, i would just collect some and use that. I have also heard that urine has many nutrients and is sterile, that is if you done have any urinary infections, which could be good for organic growing.....as i am a newbie, i would check out my info for it may be incorrect, the learning process is a great one