Shallow Trench composting

What is “Shallow Trench” composting ?

After years struggling to create compost quickly and effectively, I had a brainwave to heap about 3 wheelbarrow loads of woodchips into a shallow trench. Within a couple of months they had completely broken down to a usable soil conditioner. Which compared to a similar pile heaped into a plastic compost bin, had just dried out and was still struggling to break down after 6 months.

Like Open Book planting beds, shallow trench composting is about working with the water profile just beneath the grass layer on your plot. We are going to use the same principles as those discussed in Open Book planting bed to speed up the rate at which water is transpired through our sunken bank of compost. Because remember it is microbes that break down the lignin in the wood and they need water and nutrients to work.

We are going to do this by digging a 4″ deep trench by 30″ to 36″ in width and as long as the amount of material you have to create a reasonably sized mound within this trench. Its best to site this trench in a shaded part of your plot so as to keep moisture levels high in your compost mound. I also built a shallow wooden duck board (made from pallets) to lay at the bottom of the trench and filled the spaces between the slats with flints & stones to improve air flow through the bottom of the mound. We will use the soil removed from this trench on our newly created “Open book planting beds”.

After a few months the chips had completely broken down and the duck board allowed me to cleanly run my spade along the slats and scoop up the composted wood chips for us on my plot.

see Diagram and photo.

It is only recently that I came across a video on utube showing sort of the same idea. However my design allows air to flow under through the stones into the mound. Doug made his video around the same time that I was experimenting with my trench. I can’t honestly say if I’d watched his video and subconsciously it got stored away.

uTube video – Doug Green – Trench Composting