Is Urine Safe for Gardens?

I first wrote about using urine in the garden in 2013, in Free, Homemade Liquid Fertilizers for Mother Earth News. The magazine hired Dr. Will Brinton of Woods End Laboratories analyze plant nutrients that could be leached from common organic materials, including grass clippings, manure and human urine. You can view the report here, but the bottom like is that urine is a salty but serviceable nitrogen fertilizer when diluted with water 20:1.

Many readers had questions about sanitation. Could using urine in the garden cycle unwanted microbes into the soil? Several physicians weighed in, and a caveat should be added about using urine from individuals undergoing chemotherapy or otherwise taking funky drugs. The rest of us produce clean urine that can be diluted and used as a liquid fertilizer, or deposited in convenient pee bales.

Can Urine Be Stored?

For several years I spoke at the Mother Earth News Fair in Seven Springs, Pennsylvania, which was regularly attended by an Ohio gardener named Bob. He stayed after my talks to show me pictures of his robust food garden, personally fertilized by Bob, an expert on using urine in the garden. One year he leaned over to whisper in my ear.

“I’m saving it up,” he said.

“What?”

“You know, the urine.” I decided it was time to back out.

“I bet your wife loves that,” I said, and he told me of his stash of stored urine in milk jugs in the garage. No, Bob was not nuts. Stored urine is not as strong as fresh urine because the nitrogen degrades into ammonia, which Bob found easier to use in his garden. And, should you be concerned about strange bacteria in stored urine, recent research from the University of Michigan found that any microbes in fresh urine die after leaving the body. Urine stored for six months cannot support microbial growth.

Not being a personal expert on storing urine, here I must refer you to the good work being done in Battleboro, VT, by the Rich Earth Institute. Please visit their website to learn more about their research on stored urine.

Using Pee Bales in the Garden

When a pee bale is ready for replacement, I let it dry out for a few days to make it easier to handle. Then I glove up and use a digging fork to move the decomposing bale to the garden in a wheelbarrow. A new bale is moved to take its place.

I don’t really know what’s in a broken-down pee bale, biologically speaking, but I assume the straw fibers are heavy with salt. For that reason, I prefer to use the rotting straw as a thin mulch so that rain and watering will leach the salt and nutrients in an even pattern. The last pee bale I harvested was spread over fall-planted garlic as a winter mulch. The one before that mulched the bell peppers. The next will go on the asparagus bed.

Occasionally I will catch a little whiff of urine from the pee bales, so I assume they emit a strong odor to animals with stronger olfactory senses, like deer, bears, raccoons and coyotes. Oddly enough, the wild creatures do not seem particularly repelled by the pee bales, so they probably get used to it.

I don’t know about zombies, though. Can they smell anything at all?