If you’re looking for a powerful, free, and sustainable fertilizer, look no further than your own bathroom. Learning how to mix urine for fertilizer is a simple and effective method that gardeners have used for centuries to boost plant growth.
Human urine is rich in nitrogen, phosphorus, and potassium—the primary nutrients in commercial fertilizers. When used correctly, it can give your vegetables and flowers a remarkable growth spurt. It’s a fantastic way to recycle nutrients and reduce your environmental footprint.
This guide will walk you through the safe and simple process. You’ll learn why it works, how to prepare it, and which plants love it the most.
How to Mix Urine for Fertilizer
This is the core process. The key is always dilution. Fresh urine is too strong for plants and can harm them and soil life. Follow these steps for a safe, effective liquid fertilizer.
What You’ll Need
- A container for collection (like a dedicated bottle or bucket).
- A larger container for mixing (like a watering can or 5-gallon bucket).
- Fresh water. Rainwater is ideal, but tap water left to stand for a day is fine.
- A stirring stick or spoon.
The Step-by-Step Mixing Process
- Collect the Urine: Use a clean container to collect urine. It’s best to use it fresh, within 24 hours, to minimize odor and prevent urea from breaking down into ammonia.
- Dilute It: This is the most important step. The standard dilution ratio is 1 part urine to 10 parts water. For tender seedlings or potted plants, use a weaker mix of 1:15. Pour the urine into your watering can first.
- Add Water: Fill the rest of the watering can with water. If you’re using a bucket, for example, add 1 cup of urine to 10 cups of water.
- Mix Gently: Stir the solution well to ensure it’s thoroughly combined.
- Apply Immediately: Use the mix right away on soil around your plants. Avoid splashing it on leaves, especially in sunny weather, to prevent burning.
- Water the Soil First: For best results, water your garden with plain water first if the soil is dry. Then apply your urine fertilizer to already moist soil.
Important Safety and Hygiene Notes
Only use urine from healthy individuals not taking strong medications. It should be generally odorless and light in color. Do not use it if you have a urinary tract infection.
Always wash your hands after handling. While the diluted fertilizer is safe, practice basic hygiene. Also, it’s wise to rotate application spots in your garden and not use it exessively in one area.
When and Where to Apply
Apply your fertilizer mix to the soil, not the plant. The best time is in the early morning or evening. This gives plants time to absorb the nutrients without the sun causing rapid evaporation.
Feed your plants with this solution no more than once every two weeks for heavy feeders like corn and tomatoes. For other plants, once a month during the growing season is plenty. Always observe your plants response.
Plants That Thrive on Urine Fertilizer
- Leafy greens (lettuce, spinach, kale)
- Corn
- Tomatoes and peppers
- Squash and cucumbers
- Fruit trees (applied to the root zone)
Plants to Avoid or Use Sparingly
- Seedlings (use a very weak 1:20 ratio if at all)
- Legumes like beans and peas (they fix their own nitrogen)
- Small potted herbs (they prefer poorer soil)
Why This Method Works So Well
Urine is a nearly complete fertilizer. About 90% of the nitrogen we excrete is in our urine, along with significant amounts of phosphorous and potassium. These are the N-P-K numbers you see on fertilizer bags.
When you dilute it properly, you create a fast-acting, liquid plant food that’s readily absorbed by roots. It mimics the action of expensive synthetic liquid feeds but is completely natural and free. The process closes a nutrient loop, taking what we don’t need and giving it back to the soil.
Advanced Tips for the Committed Gardener
For even better results, you can compost your urine. Adding it to a carbon-rich compost pile (with straw, leaves, or sawdust) is an excellent method. The carbon soaks up the nitrogen, creating fantastic compost later.
Some gardeners also add a bit of wood ash to their urine mix. The ash provides potassium and helps balance the acidity. But this is optional and requires careful measurement—too much ash can make soil too alkaline.
If your concerned about salt buildup, which can happen with any fertilizer, ensure you are watering deeply with plain water between feedings. This leaches any excess salts away from the root zone.
Troubleshooting Common Issues
Odor: If your diluted mix smells strongly of ammonia, it’s too old or not diluted enough. Use it fresher and increase the water ratio. Applying to soil immediately also prevents odor.
Plant Burn: Yellowing or wilting leaves after application means the mix was too strong. Always err on the side of more water. Flush the soil with plenty of water to help the plant recover.
Soil Acidity: Long-term use may slightly acidify soil. If you use it regularly, test your soil pH annually and add lime if needed. Most vegetables prefer a slightly acidic to neutral pH anyway.
Frequently Asked Questions (FAQ)
Is it safe to use human urine as fertilizer?
Yes, when handled correctly. Urine from a healthy person is typically sterile when fresh. The key is proper dilution (1:10) and application to soil, not plants. It breaks down quickly in the soil.
Can I store urine for fertilizer?
It’s best used fresh (within 24 hours) to prevent odor from ammonia formation. If you must store it, keep it in a sealed container in a cool place, but be prepared for a stronger smell when you open it. Dilute it as soon as possible.
Does urine fertilizer smell bad?
Properly diluted and applied to soil, there should be no lingering odor. The soil microbes quickly process the nutrients. Strong smells indicate you need to dilute it more or use it fresher.
What is the best ratio for mixing urine and water?
The standard and safest ratio is 1 part urine to 10 parts water. For very young plants or in containers, use a milder 1:15 ratio. Never use it straight from the source.
Can I use urine fertilizer on all my plants?
Most plants benefit, especially nitrogen-hungry leafy greens and fruiting plants. Avoid using it on legumes like peas and beans, as they produce their own nitrogen. Be cautious with seedlings due to their tender roots.
Using urine as fertilizer is a powerful technique for any organic gardener. It turns a waste product into a valuable resource, saving you money and improving your soil fertility. By following the simple dilution method of 1:10, you can safely feed your plants and witness impressive results. Remember to start with a weaker mix if your unsure, and always apply to moist soil. With a little practice, this age-old method can become a cornerstone of your garden’s health.