can you compost urine?
Yes, but on the pile, not the garden — urine is a free nitrogen activator best poured over carbon-heavy compost a little at a time.
breaks down in Absorbed in days; nitrogen available almost immediately
which bins can take it?
- hot pile yes
- cold pile caution
- worm bin no
- bokashi no
- tumbler caution
- curbside no
- cold pile: Fine as an occasional nitrogen boost, but slow piles vent more of it as ammonia smell.
- tumbler: Enclosed drums trap ammonia and free liquid — a splash at most, with dry browns to soak it up.
- curbside: Curbside programs collect solids only — no liquids of any kind.
why?
Urine from a healthy person is close to pathogen-free and loaded with urea — the same compound sold in bags as 46-0-0 fertilizer — so a straw-and-leaf pile treats it as rocket fuel. Bacteria convert the urea to ammonium within days, feeding the heat-generating microbes that carbon alone can't sustain. The limits are salt and smell: sodium builds up with repeated soakings, and surplus ammonia escapes as odor when there isn't enough carbon to grab it.
how to prep it
- Pour onto dry browns — straw, leaves, shredded paper — not onto finished compost
- Rotate spots and ease off if the pile starts to smell of ammonia
watch out for
- Skip it if you're on medication — drug residues pass through in urine, and composting doesn't reliably degrade all of them.
- Anyone with a urinary tract infection should keep urine out of compost destined for food gardens.
- Salt accumulates with heavy repeated use; occasional additions are the pattern extension guidance supports.
quick answers
Why isn't urine considered a green?
Its carbon-to-nitrogen ratio sits below 1:1 — so low it isn't really a material at all, just dissolved nitrogen. Think of it as liquid fertilizer for your browns rather than an ingredient with bulk.
Is composting urine legitimate or just an internet hack?
It appears in university extension guidance and field research as a genuine activator — urine-fed straw piles heat up faster than plain ones. The taboo is social, not microbiological.