Creating the Right Environment
Here is what you need to get started:
- A ventilated container with drainage
- Red worms
- A food source such as kitchen scraps
A container such as a 14-gallon (or larger) plastic tote or a bin made of untreated wood works well. It needs to be covered to keep light, flies and other pests out, and have air vents and drainage holes. A bin that is 8-12” deep is best.
Bedding can be a mix of shredded newspaper, small pieces of cardboard, coir (fiber from the outer husk of the coconut), peat moss, straw and/or leaves. Combine two or three types of bedding to create air space and allow for movement of the worms. Include a handful of vermiculite or soil with the bedding to give the worms grit to aid their digestion. Fill the bin ¾ full of bedding and moisten. It should feel as damp as a wrung out sponge. Worms breathe through their skin and need moisture to survive. If the environment becomes too dry, they will try to escape or die. As the worms eat the bedding and the level falls, add more bedding to keep it at the original level.
Worms do not eat the food scraps directly; they consume the microbes on the decomposing food. Cutting up large or hard pieces will increase the rate of decay. Leaving the scraps to mold is another option. Do not liquefy the scraps as this will cause the bin to become too moist, creating anaerobic conditions which are toxic to the worms.
Red worms will eat most kitchen scraps but some of the waste will cause odor or pest problems. DO NOT feed the following:
- Meat, fish
- Dairy products
- Oily foods
- Pet feces
- Citrus (unless it is first left to mold before adding to the bin)
Where Can I Keep My Bin?
The worms are most active when the temperature is between 55F and 75F. The most common location for bins is outside in an area protected from direct heat and cold. In cold weather, insulate the bin by covering it with an old sleeping bag, old carpet or even straw bales around the sides and top. In summer, keep it in a shaded area. Smaller bins can be kept in the garage or other spaces that have moderate temperatures. Inside bins need a tray or additional bin underneath to capture leachate.
How Does it Work?
By creating a moist debris pile in a box, you are creating conditions in which worms thrive. As the worms multiply, increase the food supply. Bury the food about halfway down in the bedding. Leaving food on top will attract flies and other pests.
A properly maintained worm bin will smell sweet and earthy.
Overfeeding or too much moisture can create anaerobic conditions giving off a stinky smell. Add dry bedding to soak up excess moisture and cut back on feeding. Rotate the placement of the food scraps in the bin and, if the original food is not consumed in a few days, stop feeding until the worms catch up.
Fruit flies and fungus gnats are attracted to anaerobic conditions and especially to the alcohols that anaerobic bacteria give off as they reproduce. Bury the food in the bin or keep the top layer covered with damp newspaper. Fluff the bedding occasionally to keep air circulating. Remove pests such as slugs and snails. These feed on worm cocoons and will dramatically reduce the new generation of worms. Wooden bins kept outdoors will need hardware cloth over ventilation holes to prevent mice and rats from entering.
Harvesting the Vermicompost
Finished worm compost can be harvested in four to six months. The most common methods are:
Dump and Sort (recommended)
This method relies on the worms’ aversion to light. Dump the contents of the bin onto a plastic covered table in the sun or under a bright light forming many small cone-shaped piles. Wait 20 minutes. (You can use this time to clean the bin and add fresh bedding.) Working on one mound at a time, scrape the vermicompost off the top and pick out any worms that have not migrated. Mound up again and repeat the process. As the worms seek to avoid the light they will work their way to the center of the pile and you will be left with a pile of vermicompost to one side and a mass of worms at the bottom of the original pile. Place the worms back in the bin with fresh bedding and begin the process of vermicomposting all over again.
Bait and Switch (this method only works with large bins more than 2 cubic feet in volume.)
Stop feeding the worms two weeks before starting this process. Move the finished vermicompost to one side of the bin. Place fresh bedding in the empty side. Moisten and feed on that new side only. Do not cover the vermicompost and worms on the old side with bedding; leave that side to dry out. Over the course of a month the worms will migrate to the moist side and the new food source. You may dump and sort the finished compost for the few worms that remain. Remember that egg cases may be in the finished compost and baby worms will be incorporated into any planting mix. Don’t be surprised to see new worms where you least expect them!
Using the Finished Vermicompost
Worm castings are a rich source of beneficial bacteria and other microorganisms and a wonderful soil amendment for plants. use vermicompost in the planting hole when setting out seedlings and to augment your garden soil.
Composting with Worms
Worms are one of nature's star composters. Red worms (Eisenia fetida) live in the top layer of soil and consume the decaying organic debris which is found there. By creating suitable living conditions, we can take advantage of the red worm's ability to recycle organic matter.
Worm bin composting (vermicomposting) uses red worms in an enclosed container to convert vegetable and fruit scraps into a nutrient rich soil amendment they excrete called castings. Vermicast or vermicompost is a mixture of worm castings and decomposed organic matter. When harvested and applied, vermicompost provides beneficial microorganisms and nutrients to the soil. Worms eat half to their full body weight each day in food scraps and bedding. How do these worms maintain a "waistline"? Perhaps it's their waste line!
Unlike earthworms, red worms are not deep soil dwellers. They live in the loose upper layer of soil and you will often find them in mulch, compost and manure piles. A pound of worms needs at least one cubic foot of space to thrive. A 14-gallon tote, 3/4 full, provides about 1.5 cubic feet of area for the worms. Worms eat more or less depending on the temperature, level of decay in the food provided, and their level of happiness. As you learn how much your worms consume, you can modify the amount of food. Don't add more scraps until the worms have consumed most of what is there.