Worm Bins
A bin serves to contain the entire vermicomposting operation (bedding, worms and food). It should be of solid, opaque material (worms do not like light), with a tight lid (to contain possible odours and help keep away fruit flies), ventilation holes and drain holes in the bottom. To help maintain aerobic conditions for the worms, horizontal surface area is more important than depth.
Worm bins may be constructed, adapted or purchased. Covered plastic storage containers can also be adapted as worm bins through the addition of drain holes and ventilation holes. In recent years, commercial worm bins have come on the market. These are available from bulk composting worm suppliers.
To enhance the durability of wooden worm bins (especially those left outside for a time), the outside surfaces should be painted or treated with a marine varnish. Interior surfaces in contact with the moist bedding material can be sealed with paraffin wax and interior joints caulked with bathroom silicone.
The rule of thumb in efficiently sizing a residential worm bin is:
- One square foot of horizontal surface area for every pound of kitchen waste added each weed (0.2 square meters per kilogram per week).
For efficient food waste processing, the initial requirement for redworms is:
- One pound of worms for every half pound of kitchen waste added per day (one kilogram per half kilogram per day).
A lesser weight of worms may result in the temporary generation of odours until the worm population multiplies enough to handle the excess food supply. Conversely, an oversupply of worms will soon die off sufficiently to just match the rate at which food is added to the bin.
Assuming that proper environmental conditions are maintained, food supply is the limiting factor in a worm a bin. In miniature then, worms exemplify perfectly the Malthusian axiom that "population, when unchecked, increases in a geometric ratio."