The Compost Tractor Method

Easily make new garden beds while creating good compost.

This article was written by my friend Rick Valley. He was one of Easy Digging's earliest customers and has stayed in touch with us over the years. Rick is the Land Steward at Lost Valley Education Center in Oregon. I have made some edits to the article Rick sent us. A longer version appears in Good Tilth magazine. Any typos, errors, or omissions are mine.

Thanks for reading! by Greg Baka

The "Compost Tractor" method of creating rich garden beds
by Rick Valley (Photos by Charles Newlin)

I have considered myself an accomplished composter since way back in 1990 when I took a permaculture class at Frank and Karen Morton's Shoulder to Shoulder Farm in Oregon. Back then I was composting restaurant scraps to produce enough compost to make container mix for my small nursery, as well as managing composting for a co-housing community.

Frank Morton showed us something new about composting. He had observed that a compost pile leaves an excellent planting bed behind after the compost is removed. He was building large piles where he wanted garden beds to be, and then moving any unfinished portions of the pile to the location of the next planned bed. He called the advancing pile his "compost tractor" and it is a brilliant way to pioneer garden beds.

I brought the technique to Lost Valley Educational Center when I took the Land Steward job there in 2004. The soil there was quite poor and leached of nutrients. The people at Lost Valley were talking of increasing food production, so an increase in compost production was called for. I increased the length of the piles and started the "compost tractors" rolling across three different gardens, leaving fertility in their wake.

So how does someone in their late 50's with chronic back problems turn the cubic yards of compost needed to seriously improve soil conditions on acres of gardens? The secret is that the human body is stronger pulling than lifting. Turning a compost pile with a common garden fork is especially difficult if there are branches or vines mixed in it. The most abundant biomass for compost feedstock at Lost Valley, as in most of western Oregon, is blackberry canes and Scots Broom slash. Add in as much English Ivy as you can stand to pull, and you'll win the love of any native plant enthusiast!

sketch or schematic of compost tractor system

Schematic of the system. Click for a larger image.

Using a fork hoe to move a compost pile forward.

The best tools I have found for turning these compost piles are fork hoes or narrow-bladed eye hoes. Light weight and strength are crucial. The English-style three tine fork hoe (Canterbury hoe) was originally imported by Smith & Hawken, but now only available from Easy Digging. It now has a longer handle which helps you reach across a compost pile. There are also eye hoes (grub hoes) with a 4 inch wide sharp blade. With such a tool you can loosen the undigested cover layers, chopping them and even laying them down on the new bed for the aeration/base layer in a single swing. Further down in the layers, the hoe can strip the undigested sides, eventually getting down into the "paydirt", the dark and ready-to-use thermophilic compost that can be taken away for potting mix, top dressing for an older bed, or for making compost tea.

Fork hoes are extremely useful for the building of the piles, and a pile is being built anytime a pile is turned. If the heavy breaking-up job has been done with a sharp grub hoe, then a heavy compost fork hoe is not necessary. I often use lighter forks for grabbing and placing stray bits, moving lighter materials to the new pile from my wheelbarrow, and arranging the layers in the new pile.

Pulling out the undigested sticks from the heavy layers of finished compost is another job for a fork hoe. With this easier turning method, coarse materials can be included in the pile. This rapidly adds volume to your production of compost. Undigested sticks which are moved to a new pile carry all the innoculating microorganisms you could wish for, and help a new pile heat up quickly. I was gratified to learn that Sir Albert Howard (the man who coined the term organic agriculture) thought that woody branches were a crucial ingredient of good compost.

The "compost tractor" can be moved pretty quickly. Once I have the materials for a new pile ready at hand (see list below for typical ingredients) I can pull the leftovers from a bed-ready compost pile over to a neighboring position and mix in the fresh material to create a new 30 foot long pile in one morning. Typically we would put three people on the project and do it more quickly, with both forks and hoes in play simultaneously, just because it's faster and more fun that way.

Composting Materials - listed by general role in the pile:

Nitrogen: the fuel for the microbes

coffee grounds, fish waste, lawn clippings, urine mixed into animal bedding, chicken coop litter, manure (which is especially valuable for the microbiology included), and prunings from any nitrogen fixing plant

Carbon: the body of the compost

All chopped or broken to less than 2 foot long: tree branches, cornstalks, shredded paper, cardboard, straw, scythed hay, tree service chips, hedge clippings, blackberry slash, fruit tree prunings, ivy

Mineral: improves the plant nutrient uptake

earth from the chicken yard, clay slip (subsoil mixed in a bucket of water to a slurry), turf (cut sod that has been stacked upside down, covered with mulch, and aged for 6 months)