by Christina Bertea
Having studied every example I've seen, and even built one at a community garden, I finally decided to experiment with peepeeponics in my own backyard where I can monitor it carefully.
I lined an old galvanized garbage can with several large plastic garbage bags to prevent the urine from reacting with the metal (if you use a waterproof plastic or rubber garbagecan you don't need to do that.) I filled the bottom 2/3 with carbon of various sizes so it wouldn't compact-- shredded cardboard, straw, wood chips, dried leaves--dry brown woody stuff. Then I put a piece ofpipe 1-1/2 to 2" diameter with an open end right on top of all that carbon, reaching up high enough above the top of the can to be above whatever I thought I might plant.I filled the top 1/3 of the garbage can (around the pipe) with light fluffy humus rich soil. I planted nitrogen hungry plants in the soil (usually leafy greens like a lot of nitrogen). Then I harvested my pee in a Click and Clack airtight container (so the ammonia wouldn'tescape and my bathroom wouldn't smell like a latrine) and began transferring that liquid gold daily into a funnel that pours it through the pipe directly down onto the carbon--the pee never touches the plants or the soil. The photo at left is of my garden experiment with very happy lettuce!
This system was developed by Francisco (Paco) Arroyo in Mexico City where he was teaching poor farmers who had migrated to the city, how to grow vegetables for their families. Nik Bertulis has been teaching the system to us locally.
The community garden peepeeponics had a "pee booth" with urinal/funnel (for the guys) delivering pee to the top of the carbon inside the lined wooden container. (You can just see the tube coming through the recycled convention banner curtain.)
Apparently the nitrogen in the pee immediatelybegins to compost the carbon, turning it into plant-available nitrogen. The moisture and nutrients wick up through the soil to the plant roots, and the vapors from the biological process waft up and are caught by the soil so no smell escapes. Theoretically you have to water very little and indeed my lettuce seems to be doing fine in the sun without top watering. Eventually of course the carbon will turn to compost and I will empty it into the garden andstart all over.
This is a great way to capture all the nitrogen, phosphorus, and other valuableplant nutrients that are in our urine.