I know it sounds a little weird or even gross to use pee on plants, but urine is a good fertilizer. It contains some of their most needed nutrients, like phosphorus, potassium, and nitrogen, a byproduct of eating protein, and those nutrients are in a form that is easily absorbed by vegetation.
As we digest our food, our bodies reduce it to the most basic minerals, making it perfect for plants to take up as fertilizer. Some horticulturalists are super into using pee in the garden—researchers in France are even considering urine as a more sustainble substitute for chemical fertilizers—but before you pop a squat over your pots, there are some details to be aware of.
How to use pee as a plant fertilizer
As long as you’re healthy, urine is pretty much sterile when it comes out, though you should take a few steps to make sure it’s in the best shape it can be for your plants. “The first thing to note when intending to use human urine as fertilizer is that the urine is too concentrated,” says professional gardener Miguel Palma, owner of the gardening advice site Jardin Tienda. “It should be diluted before application.” Otherwise, it can burn the leaves or kill off micro-organisms that you need in the soil.
The best way to put your pee to use? Collect it in a container with a lid (aka pee in a big bottle—there are funnels women can use to make it easier) and then pour some pee into a watering can and dilute it with five to 10 parts water. The ratio doesn’t have to be exact, you can just eyeball it. Then water your garden, pouring it around the plant bases instead of directly on the leaves. It works best when applied to actively growing plants before they grow fruit or seeds.
“You can do this at home and save on the cost that would have been used to buy fertilizers,” Palma says. But if you’re worried about the smell, it should dissipate pretty quickly, or you can add some vinegar to the container while it’s empty to counteract any odors.
Another factor to consider is the temperature of the soil, which should be at least 50º F to make sure the plants are warm enough to absorb the nutrients. Urine also has salts in it, and salt is not great for your plants. As long as you water well between pee applications, the salts will be diluted and you won’t have a problem. If you start to see scorched leaves, wilting, or a white crust on the soil, your salt levels are too high and you need to dilute the urine more and water with more pure water between fertilizations.
Is using pee on your plants safe?
The Rich Earth Institute, headquartered in Brattleboro, Vermont, researches the safety of using urine on crops for eating and is using donated human urine to make commercial fertilizer for sustainable farming. They recommend always being transparent if you’re giving produce from your garden that was fertilized with pee; it’s just good manners. Wash your hands after handling urine and wash your fruit and vegetables before eating them—two things you should already be doing anyway. The institute also recommends waiting at least a month after pee fertilization to harvest anything that you’ll eat raw. Their Guide to Urine Fertilizer for Home Gardens has some great information if you decide to join the pee revolution.
Bottom line: Using urine to fertilize your garden is safe, effective, and—best of all—free. But do you want to? It completely depends on your own personal ick factor. If you can’t get past our societal “ew, pee” reaction, then it’s probably not for you. But if that’s not a big deal to you, try it and see if your garden grows better.
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