Vermicomposting, often called worm farming, is an efficient and environmentally friendly method of converting organic waste into a valuable soil amendment called vermicompost, or worm castings. This process uses specific species of worms to quickly break down food scraps and bedding materials. Starting a worm farm involves a few simple steps, but attention to detail in selecting the right worms, housing, and environment is necessary for success.
Choosing the Right Worms
Selecting the correct worm species is the first and most important step, as not all earthworms are suited for composting kitchen scraps. The preferred species for home vermicomposting is the Red Wiggler (Eisenia fetida), because of its high efficiency, rapid reproduction, and tolerance for bin conditions. These worms are known as epigeic species, meaning they naturally live and feed on decaying matter near the soil surface, making them ideal for the confined environment of a worm bin.
A common alternative is the European Nightcrawler (Eisenia hortensis), which is larger than the Red Wiggler but typically processes organic matter at a slower rate. European Nightcrawlers also tend to burrow deeper into the bedding, which can make managing and harvesting the compost more challenging for a beginner. For a small home system, aim to start with a population density of about one-half to one pound of worms for every square foot of the bin’s surface area. Source your worms from a reputable worm grower, as non-composting species will not thrive in a bin environment.
Essential Housing Requirements
The worm bin itself must be designed to provide a dark, secure, and well-aerated home for the worms. Proper airflow is necessary for their survival and for preventing the anaerobic conditions that cause foul odors. For a DIY setup, a simple plastic storage container works well, but commercial tiered systems are also available.
The bin requires numerous small holes for both ventilation and drainage. Drill air holes, approximately one-sixteenth to one-eighth of an inch in diameter, around the sides near the top edge and also in the lid. These holes allow for the necessary gas exchange, preventing a buildup of carbon dioxide that is toxic to the worms. Drainage holes of a similar size should be drilled into the bottom of the container to allow any excess liquid, known as leachate, to escape. The bin should be placed on a tray or saucer to collect this liquid, ensuring the bedding does not become oversaturated, which can lead to a waterlogged, unhealthy environment.
Preparing the Bedding and Environment
The bedding serves as the worm’s habitat, providing moisture, air, and an initial food source, and must be prepared before the worms arrive. Suitable materials include shredded corrugated cardboard, non-glossy newspaper strips, coco coir, or peat moss. A combination of materials is often beneficial, as it provides a better mix of texture and nutrient availability.
The bedding must be thoroughly moistened to reach the consistency of a wrung-out sponge, which is damp enough to hold its shape but not dripping water when squeezed. Fill the bin about two-thirds full with this fluffy, moist bedding to allow room for feeding and movement. Introducing a small amount of grit, such as pulverized eggshells or a handful of soil, helps the worms’ gizzards grind down food, as they lack teeth.
Initial Feeding and Placement
After the bedding is prepared and the worms have been gently introduced to the surface, they need time to acclimate to their new home before heavy feeding begins. New worms should be allowed to settle into the bedding for two to three days without any food scraps. When you do begin feeding, start very slowly with a small amount of food in one corner of the bin, only adding more once the initial food has been mostly consumed.
Appropriate starter foods include fruit and vegetable scraps, coffee grounds, and tea bags (without staples). Avoid foods like meat, dairy products, oils, and citrus fruits, as these can attract pests and create an acidic environment harmful to the worms. The bin should be placed in a location where the temperature remains consistently between 55°F and 77°F, which is the optimal range for Red Wigglers to feed and reproduce. Direct sunlight must be avoided, as it can quickly overheat and dry out the bin, making a basement, garage, or shaded outdoor area ideal.