How often to fertilise?

Some people use urine fertiliser up to twice a week, others only twice a month. It depends on the plant and on lots of other factors like rainfall and how well your soil drains. It’s up to you to try out and see what works.

Signs of nitrogen deficiency include yellow or pale green leaves.

Signs of nitrogen excess can include over-producing leaves (at the expense of fruit and flowers) and curled leaves.

Will it smell?

Fresh, healthy pee doesn’t smell. After around a day the urea breaks down into ammonia which can escape as a smelly gas. This is why we work it into the soil, where bacteria will help break down the urea into nitrates rather than ammonia.

Is it dirty?

Fresh urine contains no dangerous microbes (unless you have a urinary tract infection) and we know exactly where it’s come from! By comparison, manure is more likely to spread pathogens around the garden. Urine also has a higher nutrient content than manure.

If you have an infection or are taking prescription medications such as antibiotics or cancer treatment, avoid using your urine on edible produce. It can still be used on lawns and ornamental plants. In fact, topsoil micro-organisms are likely to do a better job at breaking drugs down than wastewater treatment plants.

Some sources suggest leaving edible plants for a short period – 2-4 weeks – before consuming, especially root veg or veg that grows on the ground. Otherwise, thorough washing will take care of any unwanted microbes.

In the past, urine was an essential ingredient for all sorts of processes including textile dyeing, curing leather and tobacco, washing laundry, breadmaking and cleaning wounds and insect bites. In Britain and Ireland it was even drunk during weddings!