Instructions for setting up and maintaining a Very Basic Worm Bin

PLEASE NOTE: These instructions are meant for the folks who have purchased the 1 cubic foot Very Basic Worm Bins, but the concepts, techniques, timelines, and materials should prove useful for any type of bin or worm compost system. In the spirit of simplicity, these instructions provide only general guidelines for setting up and maintaining a bin. For more detailed information, look to our schedule for workshops and/or contact Green Noise LLC at

Instructions for setting up and maintaining a Very Basic Worm Bin

The following explains the materials that are included in your bin, why they are included, and where they can be sourced.

  • The red plastic bin is from IKEA. It is a storage bin called TROFAST. If you want more of these in the future, ask for friendly yellow-shirted IKEA representative about TROFAST bins.
  • The bedding material is coir, also known as shredded coconut husk. It is an absorbent natural material that gradually becomes part of the edible food “matrix” within the bin.
  • The fine sand is included as grit. A small amount of grit can help provide grinding material to break material down in the worms’ gizzards.
  • The calcium carbonate is included to “moderate” the pH of the bin. Depending on what you feed them, the pH of the worm bin tends to become more acidic over time. Adding small amounts of food grade calcium carbonate can help maintain more neutral pH levels that are healthier for the worms.
  • The rabbit food pellets are made mostly of alfalfa, and while these provide food for the worms, they are included to help establish the bacterial population in your bin to help ensure microbes will be present and able to start the initial breakdown of organic matter.

To setup your bin, the following steps are recommended. Always use a clean spray bottle that has not been used for cleaning chemicals or other kinds of soap or detergents.

1)      Empty contents of both bags of coir into the worm bin. If the material is excessively dry, spray with a clean mist bottle so that the contents are uniformly moist.

2)      Add one tablespoon of calcium carbonate to the coir. Spray mist and mix by hand.

3)      Add three tablespoons of fine sand to the coir bedding. Mix by hand.

4)      Place rabbit pellets in a dish of shallow water for up to 60 seconds or until the pellets begin to break apart into a mush. Remove and sprinkle the moistened pellets to the coir bedding.

5)      Open the worms and add to the bedding. You may lightly mist them.

6)      Find a good, room temperature place to store the bin that is safely away from heaters, radiators, heating vents, and cold drafts. A basement shelf, under the kitchen sink, and/or an accessible closet provide the stable temperatures and safety from pets.

Congratulations! You are finished setting up your bin.

To maintain your bin, the following suggestions and steps are recommended.

1)      Try to keep a well-rinsed gallon milk jug of water that has been sitting for at least a week near your bin. Over time, the chlorine in the water bubbles out. The chlorine that protects public water from human pathogens may discourage helpful microbes in your bin that are beneficial to worms and guide the process of decomposition. Use slightly aged water to add moisture to the bedding, when necessary. Also, use this water for filling the spray bottle, as well. Please note: The occasional use of tap water will not kill your worms, so there is no need to be overly concerned about chlorine; however, the effect of chlorinated tap water on microbes within the bin is somewhat unknown, so we recommend using aged or un-chlorinated water on a regular basis.

2)      A spray mister bottle is recommended for this type of hands-on worm composting system. The reason why is that the spray provides a subtle, uniform “dose” of moisture…and helps to prevent overwatering.

3)      To begin with, it’s best to add a moderate amount of food to your worm bin. For best results, it is recommended to think of your bin as having three compartments and feeding a healthy handful (or about 2-3 cups) worth of food scraps per “compartment”. Then, wait at least two and up to three weeks before adding additional food scraps. Please note: This recommendation is intended to prevent beginning composters from overfeeding their bins, which can result in anaerobic conditions and/or undesirable smells. You can speed up the process of decomposition by adding more worms, up to a point. Too many worms is like overpopulation, and can be unhealthy for worms in a limited space. Depending on the amount of bedding, this bin fits up to approximately 1000-1500 worms, comfortably. More than 2000 worms per 1 cubic foot bin would not be advised.

4)      Aerate the bin by mixing by hand once every two weeks or so. Mixing air (i.e., oxygen) into the bin helps prevent anaerobic conditions and helps supply beneficial bacteria with the oxygen they need to live.

5)      As a general practice, remember to wash your hands thoroughly with warm soapy water after working with your bin.

6)      As always, do not feed your worms food that is salty or oily or overly acidic, such as leaves that have vinegar dressing, for example. Coffee grounds in moderation are OK, but excessive coffee grounds can cause acidic conditions in the bin that are unhealthy for worms. The acidity in the coffee grounds can be adjusted by mixing 1 tablespoon of calcium carbonate per 1 measuring Cup of coffee grounds. To prevent unsafe bacteria and/or undesirable smells, do not feed animal proteins in your bin.

7)      If you have any further questions, comments, or suggestions please contact Neil Cunningham, Green Noise at

How to use your worm compost

Finished worm compost has a moist, crumbly, topsoil-like feel, and can be mixed with sterile seedling mixes as a way to add beneficial microorganisms and soil nutrients to seedlings, potted plants, and garden soils. Visit the Green Noise website in the spring for more detailed information on how to use finished worm compost at

Information created by Green Noise, 12-15-10 (Updated September 2012)

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