Let’s talk about something a little unusual but absolutely amazing for your garden—using urine as fertilizer! Before you cringe, hear me out. Centuries ago, long before modern wastewater treatment, people utilized their waste to nourish their crops. And guess what? They avoided clogged waterways and pollution from nitrogen and phosphorus. Nowadays, we tend to waste these valuable resources.
Urine is rich in nitrogen and phosphorus—key nutrients that plants need. The best part? It’s free and abundant! Research from the Rich Earth Institute in Vermont shows that one person’s urine can fertilize up to 320 pounds of wheat. That’s a lot of potential for your garden!
I know, it sounds a bit icky. But think about this: We’ve been using manure for ages, and that’s far more unpleasant if you ask me. Some gardeners are all for it, while others are on the fence. Yes, there are some concerns, but many are more about the “eww” factor than actual risks. As someone who has successfully used urine in my garden, I can vouch for its benefits.
In this article, we’ll explore how to use urine in the garden safely. You’ll get all the tips and tricks to make it work for you without any hassle.
Study Gives Green Light to Use Urine as Crop Fertilizer and Not Likely to Spread Antibiotic Resistance
The big concern with using urine in gardening has been the potential for antibiotic resistance. Even if storage or pasteurization kills the bacteria in urine, their DNA might stick around. This DNA could then be taken up by other bacteria in the soil, possibly leading to antibiotic-resistant infections in humans. Antibiotic resistance is a huge global issue, comparable to climate change in its threat level.
Fortunately, recent studies bring some good news: properly stored urine doesn’t spread these resistant genes. Dr. Krista Wigginton and her team at the University of Michigan delved into this topic. They collected over 100 liters of urine from people in Vermont and stored it for 12 to 16 months. During this storage time, the urea in the urine breaks down into ammonia, which helps kill off the bacteria.
The researchers then added plasmid DNA containing antibiotic resistance genes to the aged urine and checked if a common soil bacterium, Acinetobacter baylyi, would absorb these genes. They found that the bacteria didn’t significantly take up the resistant genes from the aged urine. Impressively, after just 24 hours, there was a 99% drop in the DNA’s ability to transfer these genes.
Further testing suggested that components in aged urine, possibly bacteria or enzymes, are likely breaking down the plasmid DNA, making it much harder for it to transfer to soil bacteria. Therefore, as long as urine is aged before being used as fertilizer—which is a standard procedure in most urine collection systems—it’s unlikely to spread antibiotic resistance.
There are some limitations to the study, such as it only looked at plasmid DNA and one type of bacterium. Still, the potential benefits are significant. If just 10% of the U.S. population collected their urine, it could provide about 330 tons of nitrogen and 20 tons of phosphorus each day.
Step-by-Step Guide to Using Urine Fertilizer
1: Collect It properly
Before you start collecting urine, it’s important to prepare properly to ensure the process is hygienic and effective. Here are a few steps to get you started:
Select a container that is easy to use and clean. A five-gallon container is a good size for collecting urine over a period. Make sure it has a tight lid to prevent odors and spills.
2: Sanitization Is Important
Should you sanitize your urine? It depends on who will consume the harvest.
- For Household Use: There’s no need to sanitize if the urine will only feed your household plants. Just ensure effective hygiene by washing your hands after handling urine or wearing gloves.
- For Community Use: When sharing the bounty with others, it’s prudent to sanitize the urine first. Store it in an airtight container at a steady temperature of 68°F for six months to kill off any potential pathogens. For a faster yet resource-intensive method, heat the urine to 176°F for 1.5 minutes.
Note that this method is more suited for larger or commercial operations.
3: Adding pH Adjusters
To minimize the ammonia smell and retain more nitrogen, add pH adjusters to your storage container. You have a few options:
- Add about four inches of wood stove ashes to the bottom of the container. This will lower the pH and prevent the ammonia process.
- Alternatively, you can add 1-2 cups of vinegar or a teaspoon of citric acid to a five-gallon bucket. Both options will help inhibit the release of ammonia.
Store the urine in a cool, dark place to further reduce the risk of odor and nitrogen loss. Ensure the container is tightly sealed to prevent any off-gassing and to keep the environment around it pleasant.
4: Diluting Urine for Use
Once you’ve properly stored your urine, the next step is to dilute it before applying it to your garden. Dilution is essential to ensure that the nutrients are delivered effectively without overwhelming your plants.
Recommended Dilution Ratio
Mix 1 part urine with 3 to 5 parts water. Some prefer a 1:10 ratio for more sensitive plants. This mix will make sure your plants get the nutrients they need without being overwhelmed.
Here’s how to do it:
- Mix three to five parts water with one part urine in a separate container.
- Strain out any remaining ashes or solid materials from the stored urine.
5: Applying Urine Fertilizer to Your Garden
Now that you’ve prepared and diluted your urine fertilizer, it’s time to apply it to your garden. This step is crucial to ensure your plants receive the nutrients they need without causing any harm.
When to Apply
- Apply during active growth periods: This is typically after germination and before the fruit or flowers develop.
- Frequent, smaller applications: Instead of a single large dose, spread out your urine applications throughout the growing season. A good rule of thumb is to wait at least one month after fertilizing before harvesting crops that will be eaten raw. This reduces any potential health risks.
- I avoid using urine on plants like lettuce and other greens because they are closely planted and it’s hard to avoid getting the leaves wet. I also steer clear of using it on root vegetables like beets, turnips, and radishes once their roots start forming.
How to Apply
Use a watering can or a similar tool to apply the diluted urine to the soil. Focus on the base of the plants, avoiding direct contact with leaves and stems. This prevents leaf burn and ensures the nutrients reach the roots.
- Wear gloves or wash hands after application.
- Apply urine close to the ground directly, rather than spraying or drenching foliage.
- For rows of plants, pour it in a strip or shallow furrow near the roots. For scattered plants, try a shallow hole nearby. With trees, apply it in a circle around the base.
- Immediately cover with moist soil, Irrigate immediately after application or apply during rain the application to maximize nitrogen absorption and prevent loss.
For plants that look like they need a nutrient boost, give them a small dose of the diluted urine. Be mindful not to over-apply, as too much nitrogen can harm your plants.
Feeding the Rhizosphere
Applying urine fertilizer feeds the rhizosphere, the critical area of soil surrounding plant roots. This underground zone is where essential nutrients are absorbed, promoting healthy root development and overall plant growth.
By integrating urine fertilizer into your gardening routine, you’re closing the loop and turning a waste product into a valuable resource. It’s a sustainable practice that benefits both your garden and the environment.
5: Adding to Compost
If you’re hesitant, you can always add urine to your compost. Urine acts as a great activator for compost piles. Dilute it as described earlier and use it to water your compost pile. This method helps reduce pathogens and retains trace minerals, even though some nitrogen will turn into ammonia and get lost in the air. This way, you still get the benefits without losing all the useful elements.
