WORM BIN SET UP

When purchasing or designing a worm bin, consider how many pounds of organic residuals you wish to process. An easy way to determine this is to estimate the pounds generated weekly, divide by 7 to determine your average daily amount. You need 2 pounds of worms per pound of waste daily. The rule is 1 pound of worms per square foot. Therefore, a 2’ x 3’ bin with 6’ surface area needs 6 pounds of worms and can handle 3 pounds of waste per day. See Feeding Your Worms (below) for more information. See Worm Bins to view small-, mid-, and large-scale commercial vermicomposting units. SAFETY TIP: Highly allergic or immunosuppressed users should consult their doctor before handling any soil product containing bacteria, molds, and fungal spores. Medical masks and/or gloves may offer sufficient protection. Pictured to the right is the Seattle Tilth OTS (“Off-The-Shelf) Worm Bin. It is built of two Rubbermaid plastic tubs and simple hardware. Plans are available at: www.seattletilth.org/resources/articles/otsbinplans. (PDF File)

CONSTRUCTING THE BIN: A simple worm bin can be made easily from a plastic tub with a tightly fitting lid purchased at a hardware or department store. The worm bin designs featured here are examples. Makeshift worm bins can be made from any nonmetal, waterproof container with a depth of greater than 8” and a width of 12”. Surface area is more important than depth, but pails work well as temporary bins. The bin pictured above is made from two tubs, forming a stacking system, but single tub bins are fine. A bin can also be made from scrap lumber, as long as the wood is not toxic to worms and other organisms. Avoid cedar and black walnut. Softwoods contain phenols and tannins which can be toxic, but highly fragrant leaves may be safe in small amounts. Redwood is apparently safe and is being used successfully in California to construct worm bins. Avoid treated lumber, which contains arsenic and other dangerous chemicals. Ventilation is critical for worms, so holes should be drilled at regular intervals on the lid, the bottom of the bin and/or the sides near the bottom of the bin. Use a 1/8” to 1/2” bit, and cover the larger holes with fine mesh screen with putty or duct tape. Holes drilled on the bottom of the bin allow both for ventilation and drainage of excess liquid, otherwise known as “compost tea”. A tray with the same length and width as the bin can be placed below. A spigot attached to the bottom of the bin at one end is another means of draining compost tea. If using a spigot make sure the bin is supported a few inches off its resting surface to allow for placement of a catch container. The image to the right is of the “Two by Three” Worm Bin by Washington State University’s Cooperative Extension Service Master Composter/Recycler Program. It is 2’ W x 3’ long and has 6’ sq. surface area. See construction plans at: www.everettwa.org/wormsite/ImgList/twobythreebin.pdf (PDF File)

FILLING THE WORM BIN:
BEDDING. Once your worm bin is built it needs bedding. Bedding is the material in which the worms live, feed, and breed. It can be made from almost any organic material. The best examples are compost and any aged animal manure. Horse manure and rabbit manure are particularly good. Cat and dog manures may be safely composted in specifically designed bin systems only. Vermicast from these systems may be used in flower beds only, not on fruits and vegetables. This is because pathogens in dog and cat waste are not killed in vermicomposting and may be spread to humans. The bacteria is especially dangerous to pregnant women or people with weakened immune systems.

Other bedding examples are shredded brown leaves, old hay or straw, peat moss (nonrenewable resource), coconut husk fiber or “coir” (renewable), or aged hay/straw/grass. Grass and other leafy yard trimmings or manure should be somewhat aged past the hot stage or worms will die. A thermometer purchased from the hardware store can be used to measure the temperature, which should be less than 80 degrees. Wood shavings and sawdust can also be used as worm bedding and are beneficial in creating air pockets, but extreme care must be taken to verify that they are safe to use (see Constructing the Worm Bin).

PAPER BEDDING. Newspaper is often recommended by vermicomposting books and web sites as bedding material because it is free and plentiful. While worms will definitely eat paper, it is not particularly nutritious and can sometimes be toxic to the worms (and humans), depending on what chemicals (including heavy metals and solvents) were used during the manufacturing process. As a rule, nonglossy, lightly colored newspaper is okay to use, as the dyes used in printing newspaper tend to be soy-based and therefore less harmful than other inks. Because newspaper and other paper products can become matted when wet, make sure you periodically fluff it to ensure adequate oxygenation. Worms tend to be quite sensitive to toxins in their environment, and their appearance and behavior are good indicators of the quality of their living conditions. If conditions are harmful to worms they will flee if given the chance, if not they will die. Nevertheless, worms are also resilient and posess the ability to digest heavy metals, human pathogens, and other contaminants to the point where levels present in predigested organic residuals are significally lower in mature worm castings." For more information click here.

PREPARING THE BEDDING. Bedding should be about 75% moist but not dripping (like the consistency of a wrung out sponge). If the bedding is too moist, extra bedding can be mixed in and if too dry more water can be added. We recommend a spray bottle or watering can. Paper/cardboard bedding should be soaked for 24-48 hours and wrung out before fluffing and adding to the bin. Yard trimmings, which tend to be too bulky for vermicomposting, should be saved instead for a hot compost pile. If adding yard or garden waste to the worm bin make sure woody items are first shredded or partly composted, as these will take longer to break down.

FEEDING YOUR WORMS:
Once bedding is in, add worms and food. Food scraps may be added either before or after the worms. See Worm Diet for details. Bury food waste in one spot three to four inches beneath the surface bedding. Bury food in a new spot every time you feed the worms to ensure that worms throughout the bin have equal opportunity. Keeping notes is helpful. You will need to occasionally add fresh bedding on top of the old bedding, as the worms will be consuming bedding and food scraps. To prevent overfeeding it is best to add more food when the old food is almost gone. This allows you to gauge how much your worms can handle. It does not matter whether you feed your worms daily or weekly. Extra food can be stored in a refrigerator or freezer for future use or can be composted outdoors. Freezing food waste has the added benefit of breaking down cell walls and allowing quicker digestion by your worms and their companions. Remember that your worm population will consume more organic waste as it grows.

STORAGE TEMPERATURE:
Eisenia fetida require a temperature range of: Minimum 38° F, maximum 88° F; ideal range 70°-80° F. If worms have a bin which allows escape to cooler pockets, worms can survive at above 90 degrees but not much higher. Emergency cool-down measures include adding ice or dry bedding to the worm bin. Dry bedding should be mixed into the existing bedding.

Worm Bin Design | Worm Bin Maintenance | Harvesting the Worm Bin

Wormpost Vermont
161 Henway Road
Morristown, Vermont (VT) 05661
Phone: 802-888-4364
Email: worms@wormpost.com