Homemade Styrofoam Vermicomposting Bins

Creating bins for compost worms brings out the resourceful, creative side of many a do-it-yourselfer. You too can take a second look at free materials at hand to improvise a shallow box to house your herd of red wiggler worms. 



By turning Styrofoam insulation boards or a discarded cooler into a worm bin, you manage a successful "green" double play. The indestructible polystyrene stays out of the waste stream and, once filled with bedding and kitchen scraps, helps create worm manure, or vermicompost.

  1. Styrofoam Panels

    • Design a vermicomposting bin to use as its sides and lid Styrofoam insulated panels, a patented name applied to the 4-by-8 foot "blue boards" of extruded polystyrene that Dow Chemical sells to insulate walls. Contractors call these blue boards; Dow calls these Super TUFF-R insulation.

      Use white glue or Liquid Nails "Projects and Construction Low Voc Adhesive" designed especially for Styrofoam to adhere the panels to a framework of 2-by-2s and 2-by-4s to create a 12-inch deep worm bin. The length and width can be 1 foot by 2 feet, or 2 feet by 3 feet, or any dimension that fits the space you envision the bin occupying, such as under a stairs to the basement. See the classic worm composting bin designs by Seattle Tilth, Bob Albert or StopWaste.org for how to create the simple box shape with a bottom and a lid.

      Use ½-inch plywood for the bottom of the bin to support the weight of the compost and use Styrofoam blue boards for the sides and lid. Omit the hinges on the lid and just loosely fit a panel of Styrofoam instead.

    Coolers or Aqua-Paks

    • Coolers and Aqua-Paks used to ship fish differ structurally from Styrofoam, being expanded rather than extruded polystyrene, even though most people refer anyway to them as Styrofoam. Both make for simple, starter worm bins. Use a pencil to poke ¼-inch holes in the bin or a drill with ¼-inch bit. Poke holes about 6 inches apart in the sides and bottom for a total of as many as five dozen in a grid pattern. Your goal is to balance the worm herd's need for air, which requires some ventilation holes, vs. its need for darkness, which requires most light to be kept out.

      Place the bin on top of a tote lid or similar lipped sheet, raised on two to four wooden blocks or pieces of polystyrene to allow excess moisture to drain out and collect.

      Some worm hobbyists prefer to keep the bottom of the cooler or Aqua-pak intact. If you do this, use a three-tined garden cultivator to lift up the bedding and inspect the bottom of the cooler for soupiness created by moist kitchen scraps. Add dry bedding material if the bin bottom seems very wet.

    Considerations

    • Worm hobbyists note that polystyrene worm bins will not survive an encounter with rats, moles or squirrels if left outside. These predators will chew through the polystyrene and begin eating your worm herd. So use polysterene worm bins indoors only.

      Try to set up your homemade vermicomposting bin so you won't have to move it. Styrofoam and cooler worm bins are more fragile and brittle than wooden or plastic bins and would be best left in place.