Been catching up with some reading in the last few days and just finished reading an article debunking some popular gardening myths.
The theory Human and animal urine is a source of nitrogen, which speeds up decomposition by boosting the activity of composting organisms.
Well, I’ve read this before. In one of my favourite books, Allotted Time, the two allotment holders seem to spend an inordinate time “watering” their compost. I’d thought about saving my own wee to give my compost bin a bit of a kick.
Would have been wasting my time, apparently:
The evidence Microorganisms are the workhorses of your compost heap and need nutrients, including nitrogen. This is found naturally in kitchen waste and green, sappy plant materials such as grass clippings. If you’ve got the right balance of nitrogen-rich and carbon-rich materials in your heap, there’s little evidence that adding extra nutrients benefits microorganisms and speeds up composting. We trialled compost activators in 2008 and found that nitrogen-rich fertiliser did not speed up composting. Too much nitrogen can, in fact, be detrimental, because it raises salt levels, which discourages worms and will turn your heap into a foul-smelling mess.
So it’s an old wives’ tale?
The verdict False: urine may be beneficial in composting if there is not enough fresh, green material in your heap, but it will not speed up composting in a balanced heap.
I use special compost bins on rollers which claim to produce good compost in a matter of 6 weeks or so. The key is to get a good balance of wet and dry matter. I have taken to using shredded paper and cardboard to give me that balance.
Over five or six years, the bins have done a fine job and I get the extra added bonus of liquid fertiliser which drains into a reservoir below the bins.
Looks like I won’t be spending a penny over the bin – so to speak.