Notes from Windward: #63
Building an Earthworm Canoeconverting plastic barrels into vermiculture grow beds
When we start a new project, the first thing we do is look around for on-hand stuff that we can use. Raising lots of earthworms will require lots of worm-appropriate containers to raise them in, and fortunately, we had just the resource at hand.
A few years back, we had access to a bunch of food-grade plastic barrels, and since then have used them for a number of things. One use involved removing the top and using them as trash barrels.
That worked well enough so long as the topless barrel wasn't let out in the August heat because the plastic would soften, and the open top would go from round to a narrow oval shape. That made them tricky to use, and looked sad.
food-grade plastic barrel with top cut off
The first step in building the "canoe" was to saw the barrel in half by starting at the narrowest part of the oval and cutting from the open lip down to the bottom. Then, flip the barrel over and again cut from the open lip down to the bottom, making sure that the second cut is 180° from the first cut.
Then stand the barrel upside down, and cut across the bottom of the barrel joining the two cuts.
plastic barrel cut in two
The next step involves overlaping the two sections and fastening them together.
The goal is to have a smooth surface on the inside of the barrel so that the barrier mesh doesn't get punctured. It's important to remember that we're building something that's not only going to contain earthworms, in the sense that they'll have an appropriate place to live, work and reproduce, but it also needs to be able to contain them in the sense that we don't want them to leave the canoe and venture out into an unforgiving world full of chickens who would also very much like to be part of the earthworm project.
Earthworms, like plants, have to have moist soil to work in, but not too moist. Just as a flower pot has a drain hole in its bottom, the earthworm canoes also have to have drainage holes in order to insure that the bottoms don't contain standing water, since worms would drown in waterlogged soil.
Consequently, the bottom of each canoe has a dozen 1/4 inch holes to insure adequate drainage. The problem is that these holes can also serve as a "wide open door" for the worms to use to escape the canoe.
We solve that problem by lining the bottom of the canoe with a fiberglass mesh, the sort that's used to prevent clay from infiltrating into a septic tank's drainfield. The mesh is coarse enough to allow water to seep through, but fine enough to hold back clay, and in this case, earthworms.
This assumes that the mesh doesn't get punctured or torn. Consequently, we use carriage bolts to bolt the two halves together since the smooth, pan shaped head of the bolt won't snag the mesh, or snag a finger when one's digs in to grab a handful of worms.
I use seven bolts to connect the two halves. In order to get a good seal between the two halves of the canoe, I start by doing the center fastener first, i.e. the 4th bolt. Then I do the two bolts adjacent to the center bolt, i.e. the third and fifth bolts, followed by the second and sixth bolts, ending up with the first and eighth bolts.
It was necessary to make the connection in that manner since by starting in the middle, each successive bolt pulled the sun warped plastic together for a tight, worm-proof fit.
two barrel halves bolted together
with carriage bolts
Well, that's pretty much all there is to it.
Once the worm canoes were bolted together, I hauled them up to Gina since she's our worm-wrangler. There's a ditch behind her place that will provide a convenient, sheltered place for the worm canoes to "over winter" as she experiments with various feed and bedding materials. Worms are known to eat a wide range of materials, from hay scraps to kitchen scraps, from leaves to shredded newspaper. Generally speaking a mix is best, but there's still a lot to work out as she scopes out the sort of buffet our worm will take to the best.
plastic barrel cut in two
Notes From Windward - Index - Vol. 63