Two recent studies, published in the J. Agric. Food Chem., showed that when wood ash was combined with human urine and used as fertilizer the results outperformed chemical fertilizers.
Greenhouse tomatoes fertilized with urine, with urine and ash compared to those fertilized with 135 kg of N/ha as a mineral fertilizer. Results showed that urine only compared equally and yielded 4.2 x more fruit than non fertilized plants growing in pots. Lycopene levels were the same but β-carotene levels were higher in those with human urine + wood ash. No enteric microorganisms were detected in any tomato fruits. “The results suggest that urine with/without wood ash can be used as a substitute for mineral fertilizer to increase the yields of tomato without posing any microbial or chemical risks.”
In a second study, the objective was to compare yield and quality of red beets by measuring microbial, nutrient and betanin (antioxidant) root content. The urine and ash hd the highest biomass at 1720 kg/ha greater than fertilized. Urine only was 656 kg/ha higher than fertilized. Nitrogen synthetic mineral fertilizer application level was 133 kg of N/ha/. Furthermore, “few fecal coliforms and coliphage were detected in mineral-fertilized and urine- and ash-fertilized red beet roots. The protein and betanin contents in red beet roots were similar in all treatments. In conclusion, this study revealed that urine with or without ash can increase the yield of red beet and furthermore the microbial quality and chemical quality were similar to the situation in mineral-fertilized products.”
Our conclusion: Empty your fireplace charcoal (wood only) in a bucket, pee on it and feed it to your plants, daily.