Urine is an excellent, free, nutrient-rich liquid fertilizer (similar to diluted liquid gold) for plants, containing high nitrogen, phosphorus, and potassium, which boost growth. It should be diluted with water at a 10:1 ratio before application to prevent fertilizer burn. Saliva is less commonly used but acts as a natural rooting aid in plant propagation, containing enzymes that can assist. [1, 2, 3, 4, 5]

Urine as Fertilizer

• High Nutrient Content: Urine provides essential nitrogen (for leafy growth), phosphorus, and potassium, along with magnesium and calcium.
• Application Method: Dilute one part urine with 10–15 parts water, especially for nitrogen-loving plants like bananas, tomatoes, and leafy greens.
• Compost Booster: It acts as a great nitrogen activator to speed up the decomposition of compost piles.
• Sustainability: It acts as a free, homemade alternative to commercial fertilizers, reducing nutrient waste.
• Safety Note: Fresh human urine is generally sterile, but it is advised to use it only from healthy individuals and not from those on medication. [1, 2, 3, 4, 5]

Saliva in Gardening

• Rooting Aid: Some gardeners use human saliva on cuttings (e.g., succulents) as a natural rooting hormone, due to enzymes within the saliva that can encourage root growth. [1]

Commonly Used Plants for Urine Fertilizer:

• Bananas, tomatoes, corn, leafy greens, squash, and pumpkins. [1, 2]

Best Practices for Using Urine:

• Dilute: Always mix with water (roughly 1:10 ratio) to avoid nitrogen burn on plants.
• Apply to Soil: Apply to the soil around the plant, not directly on leaves.
• Quantity: It is highly effective but should be used in moderation to avoid excess nitrogen. [1, 2, 3, 4]

For more detailed, actionable advice, check out the Rich Earth Institute’s Home Gardener Guide to Using Urine as a Fertilizer. [1]