What is Vermicomposting ?

Vermicomposting is a type of compost making with the help of earthworms. It has become a popular alternative or addition to composting and has several benefits for home gardeners and organic farmers. The earthworms actually eat vegetable and fruit scraps and releases worm castings as a result it acts as a natural, nutrient rich organic compost. Vermicomposting can also be done indoors throughout the winter, whereas traditional composting slows or stops during the winter months.

How to start Vermicomposting at home ?

Vermicomposting is relatively easy. You just need to add kitchen scraps to the system few times a week. Mist with water, if needed, to keep the earthworms and materials from drying out. Add shredded paper as needed if the environment is too wet. Bins are kept in a dark place as the worms prefer a dark environment.

What type of container should I use ?

There are several options for containers :

  • Multi-layered vermicomposting systems are available from online retailers, but they tend to be expensive.
  • Less expensive options are also available which includes plastic bins, old drawers, an empty 2-liter bottle, or an empty plastic bucket.

If the bins are to remain outside, they should include drainage holes at the bottom. If the bins come indoors for the winter, do not drill drainage holes, just add a layer of gravel at the bottom of the container for excess water. Containers should have loose fitting lids that allow for air exchange but prevent worms from escaping and access to predators. Make some holes on the lid to allow for easy air circulation.

What should be the size of the container ?

The size of the container depends on the amount of scraps and also on the number of worms present in your bin. For one or two-person households with a couple of handfuls of kitchen scraps every few days, the bin can be relatively small – about the size of a large shoe box or a ice cream bucket. A family might have something a bit larger, for instance a 30 or 50 litres plastic tub.

How to set a vermicomposting Bin ?

  • Once you have identified a container, place an inch of layer of small gravel in the bottom to collect excess water.  
  • Add a few inches of shredded paper and an inch of potting soil or garden soil.
  • Mist to moisten the material and add the worms and kitchen scraps. Multiple layers of paper and soil are acceptable. The entire depth of the bin can be less than a foot.
  • The shredded paper acts as a bedding for the worms as well as a topper for the system. Moist paper on top of the bin keeps fruit flies at bay.

What type of worms should I use ?

Red wigglers or redworms (Eisenia foetida) are best for home vermicomposting as they are small, have short life cycle and furthermore are highly reproductive. Red wigglers are available at some local Vermicomposting unit or online. Nightcrawlers are not preferred because they depend on cooler temperatures and make extensive tunnels that may make the bins an unsuitable environment for long-term success. 500g of worms generally equals 1000 worms. This is plenty of worms for a family size bin.

What to feed the worms? 

Worms are vegan and therefore should only be fed scraps from fruit and vegetables. No meat, no dairy, no cheese, no bones, no manure, or any other animal product should be added to the vermicomposting bin. Shredded newspaper, copy paper, or even shredded cardboard is beneficial. Avoid adding plant materials that has insecticide or other chemical residue. Also avoid adding plastic, metal, or other non-biodegradable products.

How to maintain the worms in the winter ?

Red wigglers prefer temperatures between 12-24 degrees Celsius. Most homes maintain these temperatures during the winter months so it is best to bring vermicomposting bins indoors during the winter. Dark locations like a basement corner or under the kitchen sink are ideal. A well-maintained vermicomposting system has little or no odor. Indoors, the worms can be continually fed throughout the winter months because they do not go dormant. Ideally vermicomposting systems are not allowed to freeze, as this will kill the worms.

How to harvest vermicompost ?

The worm casting and compost are beneficial additions to garden beds and soil mixes. Finding a way to harvest this material without taking the worms out of the system can be tricky. This usually means moving the worms to lower areas in the bins and harvesting from the top. One way to move the worms lower is to open the bins and place them in a well-lit location for a few hours. The worms will move to the darker and deeper depths so that the top few inches will be free from worms.

In the summer, you can empty the bin on a plastic sheet and separate the worms from the castings and other bedding materials. This is a great opportunity to clean out the bin and place the worms into restored environment with fresh bedding and new scraps.