You may have also heard that urine is good for roses. Human urine is rich in nitrogen, as well as urea, which has high levels of potassium and phosphorus, both of which are good for roses. If you want to use human urine as a rose fertilizer, you should mix one cup of urine with eight cups of water in a watering can or jug, then pour it around your roses. Just remember that is it very strong and should always be diluted.