Wood Chippings on the Vegetable Plot

I had an email asking me about wood chippings on the allotment. It says:

I was reading the tips on clearing the allotment, the overgrown allotment. I have found it to be very useful as I've had my plot a year now and I have managed to clear it from brambles, weeds and ferns (which seem to be never ending).

Now I have got some beds in place and will soon be growing my own vegetables but there's a new problem. The allotment site have cut the boundary trees on my plot and they are now shredding them on to my plot. I don't know if they're getting rid of it but, if not, what do I do with all the tree shavings as they've covered three quarters of the plot?

Wood chippings are a natural material and will, eventually, rot down providing valuable organic matter to the soil. This improves the soil structure but doesn't add much in the way of nutrients like a manure or compost would.

In fact, there is a short term problem with wood chippings in that the process of them rotting down will cause a shortage of nitrogen. The wood is heavy in carbon so to rot down it requires a lot of nitrogen.

If you were to mulch with wood chippings, then you'd notice poor growth for a year or two until the chippings have rotted away – especially with leafy crops. Nitrogen is vital for leaf growth.

What I have found is that wood chippings are great for making paths on the allotment. They keep your boots clean in wet weather and if you move beds around can be raked up and moved. After a couple of years they rot into lovely stuff which can be dug in.

But you can have too much of a good thing and the question is "what to do with load of wood chippings?" Those that aren't used on the paths, which can take up much more than you expect, are best put into a pile to eventually rot down. This could take 3 or even 4 years! To speed up the process you need to add a lot of nitrogen. The quickest way to do this would be to mix sulphate of ammonia or prilled urea into the pile. These are fairly cheap high-nitrogen chemical fertilisers and will reduce the rotting time down to a year.

There is an even cheaper and organic answer as well. Just pee on the wood chipping pile. Urine is high in nitrogen and, being liquid, will soak into the wood helping it to reach the parts where it is needed.

Peeing directly onto the pile may not be advisable in a public place, so use a watering can in the privacy of the shed and add water to make it go further. Incidentally, urine is sterile when fresh presents no health hazard.

In a nutshell, wood chippings are useful and eventually beneficial to the plot but you need to rot them down before adding to the growing soil.