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How it Works

The process of using worms and microorganisms to convert organic waste into black, earthy-smelling, nutrient-rich humus is known as vermicomposting. The process of vermicomposting involves providing the optimum conditions necessary for your worms to live and successfully produce compost. There are three essentials for the happiness of your worms: a temperature between 55 and 77 degrees F, moist bedding needed for air exchange to take place, and ventilation throughout the worm bin for worm respiration. The worms work by feeding on the rotten organic waste added to the worm bin and the resulting vermicompost is actually a mix of worm castings and other organic materials. Among other nutrients, vermicompost contains humic acid, which is a great amendment for your soil.

Build Your Own Worm Bin

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The easiest bin set-up is a plastic tub like those most commonly used for storage. The container you choose should be shallow (8-12" deep) and provide at least 2-square feet of surface area. This size is necessary for three reasons:

  • Redworms tend to be surface feeders.
  • The bedding can pack down in a deep container, compressing the air out of the bottom layers and making it more likely to develop foul-smelling anaerobic conditions.
  • A shallower bin with greater surface area provides better ventilation and more locations to bury waste on a rotating basis.

The only "construction" required for these containers is to drill 1/2" holes in the sides and the bottom for ventilation. Once drilled, the plastic tubs must be placed on boards, or another form of support to allow air to circulate underneath. It is a good idea to place a sheet of plastic or a tray beneath your bin to catch any bedding or worm castings which may fall out. Next add the bedding, such as newspaper, to your bin. The bedding should be as moist as a damp sponge and should completely fill the bin. Next, you should add your food waste by dividing it up and burying it in different sections of the bin. You can add an average of 4 lbs. of food a week, depending on the size of your bin and number of worms, changing location each time. Red worms or red wigglers are the best to use for vermicomposting. These worms have a big appetite, reproduce quickly, and thrive in confinement. Scatter the red worms over the top of the bedding (one pound of worms is a good amount with which to start) . They will eventually migrate downward away from the light and toward the buried food waste.

Harvesting and changing bedding

As worm castings in the bin increase over time, your worms’ living quality decreases. Thus, bed changing is necessary for the worms to keep living. You should change your bin at least every 2-3 months. One technique for accomplishing this is to lay a large plastic sheet on the ground and dump out the bin, sorting the mixture into several cone-shaped piles. Shine a bright light over the piles. The worms will travel to the bottom to avoid the light. Remove the tops and sides. Repeat as necessary. Lift plastic sheet with worms and place back in the bin with new bedding. Save any vermicompost for the garden or houseplants.

What to Vermicompost

DO vermicompost:

  • Vegetable scraps
  • Fruit peelings
  • Bread and grains
  • Coffee and tea filters
  • Non-greasy leftovers
  • Eggshells