Urine as Fertilizer: Benefits, Risks & Safe Dilution Guidelines

Human urine contains nitrogen (urea), phosphorus, potassium—key plant nutrients—but requires proper handling.

Nutrient Profile (per liter, approx.)

• Nitrogen: 4–8 g (mostly urea)
• Phosphorus: 0.5–1 g
• Potassium: 1–2 g
• N:P:K ≈ 10:1:2 — high N, low P/K relative to crop needs.

Benefits

• Free, renewable, closes nutrient loop.
• Urea hydrolyzes to ammonium → plant-available N.

Risks & Mitigation

Risk	Mitigation
Nutrient imbalance (excess N)	Compost with carbon-rich material; supplement P/K.
Salt/urea burn	Dilute 1:10 to 1:20 (urine:water).
Pathogens (bacteria, viruses, parasites)	Store ≥1 month (WHO guideline) or pasteurize; apply to soil, not foliage.
Pharmaceutical residues	Avoid urine from medicated individuals for food crops.
Odor/pests	Incorporate into soil; cover.

Practical Use

Dilute 1:10, apply to root zone of non-leafy crops (corn, tomatoes, fruit trees). Not for seedlings or hydroponics. Check local regulations.