An example of trench composting. (Mary Lowther photo)

An example of trench composting. (Mary Lowther photo)

Mary Lowther column: Trench composting easier alternative to having a heap

Once the bed is full, it rests while the bed beside it gets dug up and treated the same way

By Mary Lowther

I perked up when I read about trench composting recently because it looks easier than making and using a compost heap.

One bed and path are devoted to the method: the bed is dug out down to eight or 12 inches and the soil is put on the path beside it. Compost ingredients go directly into the first bit of trench, then get covered by some of the soil on the path. This depth helps keep out varmints like our dog. I’d also put heavy mesh and rocks on top as an added protection.

The next batch of scraps goes into the same trench, beside the first batch and is also covered with soil, and so on down the line. Once the bed is full, it rests while the bed beside it gets dug up and treated the same way, until finally the whole garden has been dug up and filled with compost. By the time the first bed is planted, the compost will have broken down, not as quickly as in a compost heap because this method works less aerobically, but I think this is a great method for those of us who have enough garden space to keep a bed out of production every year, using far less effort than making a compost heap.

I’m going to give this method a try this year and since my soil is sand clear down to China, I’ll keep a bucket of clay nearby to toss a handful on each pile, along with a handful of complete organic fertilizer that I plan on keeping in a bucket beside it as well. This should attract red worms that will transform the mess into lovely stable humus. Once the bed is filled, I’ll sow cover crop to see it through the winter and plan to grow spring crops there the next year.

This is not a new method, for, as Thomas Tusser wrote in a 16th century farming calendar under November’s chore list; refuse “buried in garden, in trenches a-low, shall make very many things better to grow”. Privies were emptied too and added to the trenches.

Australians used a similar method; one that would work well for those unwilling or unable to devote a bed and path to the trench composting. Each day the young man of the family took out the family “dinny bucket” of “night soil” and put it into a hole dug into a path, presumably along with meal leftovers and other food scraps. Once the path was filled, he moved onto the next, and when all the paths had been filled, the old beds were turned into paths and the new garden was planted into the paths that held the compost. Presumably they marked where the previous hole had been dug so as not to duplicate the spot.

Given the ease of this method and the enrichment of the soil, it looks like a good system.

Please contact with questions and suggestions since I need all the help I can get.