Allison and I started off with a bottom and topless 1.5’ by 6’ long and 3.5’ tall tub made out of wood and fiberglass. After choosing the location in the garden for the bin, we gave it several coats of weather-resistant paint.
After painting it we measured out, fitted, and finally painted the two, half-inch thick pieces of wood that we would use for the double lid. Once we prepped the lids, we fastened and bolted them to the bin with T-hinges they would open the same way. Afterwards, we applied 2” fiberglass/foam insolation pads to each of the lids.
When making a worm bin, plastic usually cracks easily and the worms will eventually eat unprotected, raw wood. The upside to wood, besides the fact that it is usually inexpensive, is that it allows the bin to breathe better and it absorbs excess moisture, which can prove to be hazardous to worms. We wanted to use wood or something similar and we also wanted it to be a long lasting worm bin so we considered using chemically treated wood. We learned, however, that we shouldn’t use chemically treated wood because it can be dangerous to the worms and can leach harmful chemicals into the compost. Instead, we used fiberboard which has many similar properties to wood but is more durable and will not be eaten by the worms.
Since our worm bin would not have holes in the lid or sides, we chose not to have a solid bottom for our worm bin so that it would remain well ventilated. Instead, we set our bottomless bin on a relatively flat, hard, compact patch of dirt. We then soaked medium sized strips of corrugated cardboard ant laid them over the dirt to provide a foundation for the soil in our bin. After our cardboard foundation was set, we covered the cardboard with a thick layer of damp shredded paper. On top of the paper we dumped grit for the worms to digest their food and then more paper, smaller strips of wet corrugated cardboard, mashed up vegetables, and finally, the actual worms. After moving the worms into their new home, we laid down a thin surface layer of soil and then a bunch of moist leaves, roots, and other detritus.