Worm Diet

The chart below outlines foods that are acceptable to feed worms and wastes that are not. It is important to realize that this list is only a general guide. Certain "No Wastes" are manageable in specific types of composting and vermicomposting systems, albeit under close supervision.

 

YES WASTES NO WASTES
  1. Paper/cardboard (boxes, food packaging, junk mail, newspaper). Removing plastic windows makes the end product easier to handle when harvesting the castings.
  2. Vegetables/fruits. Chop up or crush stems and large pieces of tough vegetables. A meat tenderizer works well as a crushing implement. Food processors and blenders may also work well but create more dishes to wash.
  3. Grain products. Corn meal and other grains have been traditionally used as worm fattener and can be bought in pelleticized form. Scrap bread and flour can be added to the worm bin but may act as a catalyst, creating a quick rise in temperature which could kill the worms in a small bin. Monitor bedding temperature for safety. If the temperature is 85 degrees or above, cool with insertion of ice or extra bedding.
  4. Eggs/Egg shells. Eggshells provide worms with an excellent source of calcium. However, they can remain undigested and visible in the vermicast long after other foods have been processed, so we recommend grinding them into small particles or powder for quickest decomposition. You may also choose to add them to a hot compost pile instead of to the worm bin.
  5. Most animal manures. Make sure they (especially chicken manure) have been partially composted before adding to the worm bin to avoid overheating and killing worms.
  6. Yard wastes. Examples are leaves, grass, bush trimmings, wood chips, and sawdust. If using wood products make sure treated lumber, cedar, and other toxic woods are not included, as they will kill worms and associated organisms. Any yard waste recently sprayed with insecticides should be avoided.
  7. Human and animal hair.
  8. Coffee Grounds. Click here to read an article from Starbucks about using coffee grounds in worm bins and for general composting.

  • Peanut butter, vegetable, or animal fat/oil: Acceptable in the NatureMill indoor wormless composter.
  • Highly salty foods. A high salt content can make the worm bedding too alkaline. The salt also irritates the worms’ mucous membranes which keep them moist and allow them to breath.
  • Meat, fish, bones, and dairy products: These are not recommended for worm bins or traditional compost systems because they decompose slowly and can attract flies and rodents, and spread bacteria in the meantime. They are acceptable in the NatureMill wormless indoor composter or in a large-scale composting or vermicomposting system if handled properly.
  • Human feces. Human feces carry pathogens which are best killed through hot composting in a controlled environment.
  • Cat/Dog feces: These carry pathogens. Acceptable in systems like The Swag and the Tumbleweed Pet Poo Converter.

Worm Feeding Formula

To determine how many worms you need to compost your organic waste, you must assess how many pounds of waste you generate on a regular schedule. Since different varieties of earthworms consume feedstock at different rates, we will limit this discussion to redworms, specifically Eisenia foetida, or red wigglers. A pound of red wigglers will conservatively eat 1/2 lb. every day, so you want twice as many worms as garbage. Start with 2-3 lbs. of worms in a 6 cubit ft. worm bin. Assess the pounds of food/paper waste generated each day by dividing the total weekly weight by 7. For example, if 2 people generate 7 lbs. of paper and food waste weekly they will need enough worms to eat 1 lb. daily. This means they will need 2 lbs. of worms. The amount of food fed will need to increase as the worm population increases. Under ideal circumstances worms double their population every six months. Worms will adjust their feeding and breeding habits according to available space, so an overpopulated vermicomposting unit will result in a slower digestion rate and a slower growth in worm population. The desired capacity for a vermicomposting system is 1 lb. worms per cubic ft. of volume. It is a good idea to start with one-half the desired capacity. Having auxiliary bins on hand is convenient for housing surplus worms after harvesting.

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