Worm Composting

WHAT IS WORM COMPOSTING?

Worm composting (or vermicomposting) is a natural and efficient way to "recycle" your organic kitchen waste. Even in cold northern climates, where outdoor compost piles lie dormant in the winter, you can compost your food scraps indoors with worms, and reduce the volume of your household garbage by as much as 25%. The end result is unsurpassed as an organic soil builder and plant fertilizer.

Worm composting is easy, rewarding, and fun! Given the right environment and a little routine attention, a handful of worms will multiply rapidly and quickly digest your kitchen scraps.

To get started, you will need a properly designed worm bin, bedding material, some water and food scraps, and a crew of hungry worms.

ABOUT RED WORMS

Red Worms (Eisenia foetida or Lumbricus rubles) or Red Wigglers, are ideal for composting kitchen scraps. Unlike many other species, Red Worms thrive in the confinement of a composting bin. They require a moist, dark, well-drained and well-aerated environment. Worms are surface dwellers and will colonize only the top 6" of the bedding, where they find the best mix of oxygen, moisture, and food.

Adult Red Worms will be 2-3" long and dark red in color. The younger worms are light-colored, and shorter in length, ranging from 1" to a tiny 1/8". The tiniest worms appears as white, wiggling threads. These take about 2 months to reach breeding size. Red Worm eggs look like tiny tan beads. They normally hatch within three weeks, producing 2-7 worms from each egg. Because the small worms may adhere to bedding, take extra care that you carefully transfer all of the material to their new home.

MATERIALS NEEDED FOR A WORM BIN

Most of the following materials may be purchased at local hardware stores.

Container: You can use almost any 10 to 18 gallon, shallow, opaque container with a secure lid. A metal wash tub, plastic bin (a Rubbermaid Rough Tote is often used), or a wooden box (except redwood and red cedar, which are too acidic) will work, as long as they haven't been exposed to pesticides or other toxins.

Worms do not require a large space to do their work. The surface area required for your bin will depend on the amount of food scraps your household generates. Generally, a surface area of 1 square foot per person is adequate.

Drill or hole punch: A drill with a 1/8" bit and a 1" mandrel (or wood borer hole cutter) is recommended. Holes are needed for drainage and aeration.

Vents: One inch diameter metal or plastic vents (called "ventilating louvers" at most hardware stores). These provide aeration and keep worms in the bin.

Bedding Material: Newspaper, cardboard, peat moss, potting soil, or hardwood sawdust. Bedding provides space for the worms, absorbs excess moisture and can improve the quality of the finished compost. Peat moss is the best choice, because it's easy to use and it improves the texture of the finished compost.

Water: About 1/2 gallon of water. Worms need a moist environment to thrive.

Water sprayer: Used to keep the bedding material moist.

Soil: Several handfuls of garden soil. Soil provides minerals and grit used in worms' digestive tract.

Garden fork or hand cultivator: This is used to dig for worms and mix the materials.

Red Worms: 1 pound of worms are recommended to begin composting immediately, although any amount is acceptable. Red worms can be purchased at bait shops, worm farms, or catalogs. (see the resources section for suppliers).

DIRECTIONS FOR BUILDING A WORM BIN

• Prepare the bin before your worms arrive. Don't worry if your measurements and methods are not exact. The worms won't notice!
• Drill 20-25 1/8" holes, evenly spaced in the bottom of container.
• Drill 4-5 1" holes on the top and 2 1" holes on each side (the long side). Put the vents in the holes.
• Fill the bin with bedding material (options a or b):
• a. Shred 3 daily black and white newspapers by tearing it in half width-wise, then into 1/4" strips from top to bottom.
• b. Mix 1/3 shredded paper, 1/3 peat moss, and 1/3 dry organic material or manure or your own combination.
• Scatter soil over bedding and mix well, spraying with water until everything is wet as a wrung-out sponge (or paper can be wet first, then well drained). The container should now be about half full.
• Add worms and bury a small amount of food scraps in the bedding.
  

BIN MAINTENANCE

• Keep bins indoors or in a protected, shaded area outside (i.e. porch, garage). If you leave them outside, do not let the bin rest directly on the ground because it may attract worm-loving moles or rodents.
• Keep bins elevated one inch off the floor using bricks or wood.
• Keep the worms in temperatures between 55-75o F. (They survive between 40-84o F but are not productive).
• Aerate (turn) the materials especially at the bottom. If they are not stirred the bottom layers of bedding and food scraps will settle and produce odors.
• Keep the bedding moist as a wrung-out sponge (not soggy). Check the moisture level of the bedding weekly. Typically, it is not necessary to add additional water after the bin is constructed. If the bedding is dry, mist it with a spray bottle. If its too wet, add newspaper.
  

FEEDING YOUR WORMS

Types of food: Red Worms will process just about any kitchen scraps you have to offer. If you're interested in the nutrient value of the worm castings, aim for a varied diet. If the worms are in a large outdoor composter, you can add a small amount of dry, aged manure to boost the nitrogen content of the finished compost.

Typical foods include: Coffee grounds (with filters), carrot peels, banana peels, lettuce, apple cores, and corn meal.

Avoid the following: Salty, fatty, or acidic food, including meat bones, fish, and dairy products and non-biodegradable items like food wrappers and bottle caps.

Certain vegetable and fruit wastes, such as large pieces of broccoli, cauliflower, onion, potato, or citrus rinds are difficult for the worms to process. These should be cut into small pieces.

Food quantities: Under proper conditions, 1 pound of worms will process approximately 1/2 pound of scraps a day. It takes a little practice to familiarize yourself with how much waste the worms can process. Start slowly, adding several banana peels, apple cores or coffee grounds a day.

Feeding method:

• Cut or break up large fruit or vegetable scraps before adding them to the bin.
• Spread the food scraps in a thin layer on top of the bedding or bury the scraps in the bedding material.
• Place the food in a different part of the bin each time it's added.
• Add food scraps to the bin when they're fresh to prevent odors or fruit flies.
• When adding food scraps, stir the bedding and observe the different sizes and growth stages of the worms. (Kids love this part!)

POTENTIAL PROBLEMS AND SOLUTIONS

Fruit flies: If materials held in a container too long, fruit flies may lay their eggs in them. To control fruit flies:

• Add food scraps when they're fresh.
• Bury food scraps under bedding,
• Sprinkle calcium carbonate (lime from stone, not "quick lime") in the bin.
• Place a petri dish filled with vinegar in the bin or place the bin outside in subfreezing temperatures for a few hours (but don't let the worms freeze).

Odors: Strong odors may occur if the bin isn't maintained properly. To reduce odors:

• Reduce the amount of food.
• Stir the bin thoroughly, especially at the bottom.
• Add paper if the bedding is soggy.
• If odors persist, the best solution may be to start over, using new bedding, a minimal amount of scraps, and the same worms, sifted out of the old materials.

HARVESTING THE COMPOST

In 3 to 6 months, you should have a bin full of worm castings (dark brown tiny balls). To separate the worms from the compost, try of these three methods:

1) Remove the lid of the bin. Place the bin under a light. After 20-30 minutes, the worms will crawl down and you can harvest several inches of compost. Continuing this process until the worms have reached the bottom.

2) Place the compost in small piles on a sheet of plastic. Shine a strong, hot light (or use sunshine) on the piles. In a few minutes, the worms will crawl to the bottom and clump together. Harvest the compost.

3) Push the compost away from one side and add new bedding. Place all food scraps in the new bedding. In several weeks, the worms will have migrated to the new side.

The harvested compost can then be used as a soil supplement in the garden, landscape or potted plants. It is often necessary to add sand or peat to create a suitable soil mixture. (Worm compost can be too organic). If you have extra worms, put them in your outdoor bin or garden or give some away!

RESOURCES FOR WORMS AND PUBLICATIONS

Mary Applehoff, Worms Eat My Garbage; Worms Eat Our Garbage textbook, Flower Press, 10332 Shaver Rd., Kalamazoo, MI 49902. (616) 327-0108 (publications, worm bins and worms). You can also visit her website at http://www.wormwoman.com.

 

Brian Rosa, Environmental Supply Consulting and Services, 809 Williams St., Fenton, MI 48430 (810) 629-8622. (worms, worm bins, worm presentations).

 

"Squirmy, Wormy Composters," B. Kalman and J. Schaub, Crabtree Publishing Co., New York. (book)

 

"The Worm Digest," Box 544, Eugene, OR 97440 (503) 485-0456. (newsletter)

 

Vemicomposting", Recycling Council of Ontario (416) 960-1025. (pamphlet)

 

"Worm Composting," San Francisco League of Urban Gardeners (415)285-SLUG. (brochure)

 

"As the Worm Turns," Robert Kourik, Garbage Magazine, Jan.-Feb. 1992. (article)

Lee's Worm Ranch, Lee Allen, 2619 Bullock Rd., Bay City, MI 48708. (517) 893-4119. (worms)

 

Earthworms Eat Our Garbage
An exciting earthworm composting project at the Flint Public Library.

 

Michigan State University Extension programs and materials are open to allwithout regard to race, color, national origin, gender, religion, age,disability, political beliefs, sexual orientation, marital status, or family status. MSUE-Genesee County is funded jointly by Michigan State University, the U.S. Department of Agriculture and the Genesee County Board of Commissioners. MSU is an affirmative-action equal opportunity institution.

 

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