You can pee on compost about once or twice a week in small amounts to give your pile a strong nitrogen kick. A cup or so at a time works best. More than that and you risk making the pile too wet, which slows things down instead of helping them along.
I tried this on a pile that had been sitting cold for weeks. The browns and greens were in there, but nothing was happening. I added diluted urine to the center of the pile two days in a row. Within 48 hours the internal temp jumped from cool to the touch up to warm enough that steam rose off the top when I turned it. That was enough to convince me this trick was worth keeping in my routine.
The science behind it is simple. Human urine has a carbon-to-nitrogen ratio of about 0.8:1. That makes it one of the most powerful nitrogen sources you can get for free. Most kitchen scraps sit around 15:1 to 25:1 by comparison. Adding urine to dry carbon-rich browns turns it into a urine compost activator. It wakes up the microbes and gets them feeding fast.
Think of your compost pile like a campfire. The browns are the logs and the nitrogen is the lighter fluid. Too much lighter fluid drowns the fire. But the right amount gets everything burning hot and fast. That's what a nitrogen boost composting does for your pile. It feeds the bacteria so they can chew through the carbon material at top speed.
Stick to one cup or less each time you add urine to your pile. You can dilute it with water at a 10:1 ratio if you want to spread it more evenly across the surface. Always follow up with a handful of dry browns like shredded newspaper or dead leaves. The browns soak up the extra moisture and keep the pile from going soggy. A wet, airless pile turns anaerobic and starts to smell terrible.
If you use a tumbler, pour the urine in before you spin. The rotation spreads the liquid through all the material inside. This gives every piece of brown matter contact with that nitrogen source. On an open pile, pour it toward the center where the heat is highest. The bacteria in the hot zone will put that nitrogen to use right away.
One safety note worth sharing. Avoid adding urine to compost that you plan to spread on crops ready for harvest. Fresh urine is sterile in healthy people, but aging urine can grow bacteria on the surface of leafy greens. Wait at least one month after the last application before using that compost on food plants. For flowers and trees you don't eat from, there's no waiting needed at all.
You can also use urine to kick-start a brand new pile. Mix your browns and greens like normal, then add a cup of diluted urine to the center. This gives the bacteria an instant food source and helps the pile reach optimal temps within the first week. Without that boost, new piles can sit cold for two weeks or more before they start cooking on their own.
I now add urine to my compost every Monday and Thursday as part of my yard routine. The piles heat up faster, they finish sooner, and I spend less money on bagged fertilizer each year. It feels odd the first time you pee on compost. But the results speak for themselves when you see steam rising from a pile that was dead cold just two days before. Give it a try this week and watch your pile come back to life.
Read the full article: Compost Tumbler Guide for Beginners
