I assume you're referring to getting plant-usable nitrogen out of the urea in urine. Urea degrades slowly into NH3, and that degradation speeds up a lot if mixed in solution with urease, which is an enzyme naturally in the soil. But freezing urine ought to prevent that degradation. For one thing, gaseous ammonia can't be released in a block of ice. In general, urea in solution degrades faster with higher temperature.

Hi. Thanks v. much for your information. Here's the part that just occurred to me, nothing to do with freezing: If urease speeds up degradation of urea into NH3, why would we use urine in the first place? Do I want ammonia in my soil? I thought it was a bad thing no matter how much you diluted it. Maybe it's okay for your lawn, but how about vegetables. Thanks.

Be aware that the freezing point of urine is colder than for water. -5C, I think.

Ammonia is indeed a poison in large quantities. But in small quantities, it is digested by bacteria into the nitrates that plants need. That's called "nitrification". That's why pouring a lot of urine (or urea) directly on growing plants is, in general, a bad idea. But as a planting prep soil additive, or for compost, urine should be fine.

Thank you for the info!

Hard to imagine running short on urine.

@noki33. LOLs. I have asked the males in my household to go in a bucket, which I then deposit into the garden every day. Sometimes in the soil and sometimes on a pile of kitchen waste mixed with grass clippings. Maybe by next year it will be a most magnificent compost. Maybe.

Anyway, this is not just about nitrogen; I'd still use the urine for the small amt of minerals which are said to be there.

In that context, it's worth pointing out that the potassium and phosphorus in urine do not degrade. They'll be there forever. If you put the urine on a compost pile, the smart strategy is to bury it in the pile. Don't just sprinkle it on top of the pile if you want to get nitrates out of it.

https://www.scientificamerican.com/article/human-urine-is-an-effective-fertilizer/

There are people who do put pee directly on plants but, as I said, overdoing it is bad for the plants. Also worth noting that the salt content in urine can be high, so direct application to plants can be harmful. Of course, in compost, the salt leaches out effectively.

"Gee Whiz" is the name of the article you link to!

Don't know if anyone here remembers The Garlic Man (of Canada) Ted Maczka. He had this advice, "Piss on Everything - and Watch It Grow". Maybe this saying didn't originate with him but he liked to use it.

Here is an article somewhat off-topic that might be of interest:

https://www.sciencenews.org/blog/gory-details/urine-not-sterile-and-neither-rest-you

Re dogs' urine being unsuitable for plants. Maybe because they have a high-meat diet? Or is it the endless additives that 99% of all dog "food" contains? If hormones taken by people can end up in drinking water, it is not hard to believe that stuff in dogs' food can end up in their urine.

No, the point is that urine contains urea, and the urea, when it hits soil, releases ammonia. Ammonia combines with water and can make a seriously alkaline solution that will kill plants if there is too much of it. That's what the discussion above was about. In fact, the normal BUN of dogs is about twice that of humans, so dogs have more urea in their urine than humans do. Urea is a waste product that is generated when the liver breaks down protein. Not sure, but if dogs eat more protein than humans, that might account for their higher BUN.

Gee, if you collect dog urine for your compost pile, I guess it would be more effective in generating nutrients than would human urine. In fact, the BUN for cats is even higher than for dogs, and cats do what you need them to do. They dig a hole, pee, and cover it up! But they gotta do it in the compost pile.