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Vermicomposting: Amazing, Grazing Worms 

Think you don’t have room to compost? Think again! You can still turn your organic garbage into an amazing nutrient-rich fertilizer, even if you do not have a backyard. All you need is a little help from worms. Worm composting – or vermicomposting – is a way for you to bring organic waste recycling indoors. It requires little space and maintenance.

Vermicomposting takes advantage of natural decomposition processes. Worms and other organisms get their energy from carbon in decaying plant waste and protein from the nitrogen found in fruit and vegetable waste. The decomposers convert your leftover food and plant waste into a useful waste material called castings. Castings are rich in nitrogen, phosphorus, magnesium, and potassium so they benefit soil health.

Starting Your Worm Bin

There are four things needed for a successful vermicomposting system: a worm bin, bedding, worms, and food. Once you have all the necessary components, you can begin turning your garbage into natural fertilizer for your garden or house plants.

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Building Your Bin

A shallow container, about 6 – 12 inches deep, made from plastic or wood is ideal. Drill quarter inch ventilation holes into the sides and bottom of your container so the worms can breathe. Slightly elevate the bin over a bin lid or cafeteria tray. For details on how to build a worm bin, see Missouri Department of Natural Resources’ fact sheet.

Habitat for Worms

For bedding you can use various materials such as shredded newspaper, phone book pages, cardboard, or coconut fiber. Moisten the bedding with water and fill your bin about halfway. The bedding should be as moist as a wrung out sponge. Add a handful of soil and now your bin is ready for worms. The best worms to put in your worm bin are red wigglers, known scientifically as Eisenia foetida.

What to Feed Your Worms

Worms can eat up to half of their body weight and love any combination of plant-based food wastes such as fruit and vegetable scraps, coffee grinds, tea bags, eggshells, pizza crusts, and even oatmeal. Before placing food into the bin, increase the surface area by cutting the food scraps into small pieces, and you will significantly speed decomposition. Cover the food completely with moist bedding. Avoid dairy and meat products because they generate odors and may attract unwanted pests.

Keep an Eye on Your Worms

Maintaining a worm bin is simple but here are a couple of tips to keep your worms happy and healthy.

  1. Rotate placement of food waste.
  2. Check the moisture content. Add water if the bedding is too dry or add dry bedding and fluff, if it is too wet.
  3. If you get more fruit flies than desired, consider reducing the amount of fruit in your bin. Another option is to place a piece of cardboard or plastic on top of your buried food waste.
  4. Add a new layer of bedding to replace the bedding already processed by the worms every so often.

Harvesting Your Vermicompost

After a few months you will see that the worms have transformed the bedding into castings also known as vermicompost. This is the time to harvest. You may leave the worms without food for about a week so they completely break down any remaining food waste. Move all the bedding material to one side of the bin. Add fresh bedding and food to the other side. After several weeks, all the worms will have migrated to the fresh side allowing you to collect the finished vermicompost.

Another way to harvest is to place all the bedding material from the bin onto a large plastic covering. Divide the material into small piles. Shine a light on a pile and as the worms burrow down, remove the top portion of castings. The worms will continue to move deeper until most of the vermicompost has been harvested. Place the remaining worms and material into fresh bedding.

How to Use Your Vermicompost

Mix the finished vermicompost with soil in a garden or house plants. Add castings to seedlings and transplants. Using worm castings as a soil amendment will increase the water and nutrient holding capacity of the soil or you can simply sprinkle it on your lawn.


Appelhof, M. (1997). Worms eat my garbage: How to set up and maintain a worm composting system.

Kalamazoo: Flower Press.

Whiting, D., Card, A., Moravec, C., & Wilson, C. (2008). Soil amendments #241. GardenNotes. Retrieved

May 8, 2009, from