Should we be urinating on our gardens?

Short answer: Yes. Long answer: Ewwwwwww. From Newsday:

In 2007 the Department of Environmental Science at the University of Kuopio in Finland released results of a study that found human urine to be a great source of minerals, especially nitrogen. Scientists there had experimented with three groups of cabbage plants, treating one with commercial fertilizer, another with urine and a third with nothing. Naturally, the fertilized plants fared better than the ones that weren't treated at all. What you might find surprising, though, is that the urine-treated plants actually grew a little bigger and fuller and reached maturity more quickly and had a bit less insect damage than the commercially fertilized group.

Though this might seem gross to some, using urine for its nutrients could be a boon in places where commercial fertilizers aren't readily available or where they're just too expensive. But in our backyard vegetable patch?

"I would recommend that as an alternative, since you can save some money and you can reduce greenhouse gases, since the making of industrial fertilizers needs energy and the nitrogen fertilization industry also produces N2O (nitrous oxide), which is some 300 times more harmful than CO2 (carbon dioxide),” Helvi Heinonen-Tanski, leader of the Finnish research study, told me last week. And because our phosphorus mines are running low, with supplies estimated to last only 90 or so more years, we might be well served by exploring substitutes, like urine. "I would like to protect the lives of my grandchildren, too,” she added.

As for the risk of transmitting pathogens into our vegetables, Heinonen-Tanski says it's not much of an issue in the United States. "In principle, there are some pathogens which can be transmitted to urine, but they are really not usual in Western countries. A person having tuberculosis or bilharzia could cause risks. You do not have bilharzia in the USA, and also tuberculosis is not usual.”