Red Wigglers (Eisenia foetida) are different than the earthworms (Lumbricus terrestris) I find in my garden. Instead of processing things found in soil, such as decaying roots and leaves, or eating living organisms such as nematodes, protozoans, rotifers, bacteria, fungi, the Red Wiggler prefers our kitchen scraps. Since these little red guys (getting no larger than 5 inches in the proper environment) can eat up to three times their weight each week in such things as veggie and fruit waste, cardboard, and shredded paper, bread, and pasta (in moderation) and even coffee grounds, they are able to create compost in about 6 weeks.
How do they do it? By digesting all of the yummy (to a worm) waste and then excreting it as “castings” – more commonly known as worm poop. The process starts as the worm takes in the food by mouth, technically called their buccal cavity. It then travels through the worm's pharynx, esophagus, crop, gizzard, intestine, and lastly, their anus and out into their habitat where we humans can collect it.
These castings are full of the nutrients iron, sulfur, calcium, nitrogen, phosphorus, and potassium (NPK rating: 5.5.3). They are water-soluble, allowing your plants to easily absorb these nutrients with little chance of “burning” that can often happen with chemical fertilizers. This poop also contains good bacteria from the worm's digestive system along with fungi, enzymes, protozoa, and actinomycetes. All of this combines to create a wonderful humus that your plants will love.
But one little worm doesn't do this alone. You need an entire colony of them! Good thing Red Wigglers are prolific breeders. Did you know that worms are hermaphroditic, meaning they have both male and female organs? They join with another worm in a three-hour mating session (phew) and when complete they create a small cocoon. They can create 2 to 3 cocoons per week. These cocoons darken and harden over the next 20 days. Then the little hatchlings inside the cocoon – anywhere from 1 to 5 of them per cocoon- grow for the next three months. Once hatched these wiggly babies will mature in 9 weeks, able to reproduce again at that point.
In order to have the best success at both the reproduction process and the production of worm castings, the Red Wiggler needs a cozy habitat to do its thing. A simple rubber tote will work as an ideal environment, or you can purchase specialized stacking trays from the Internet. If you create your own you will need to provide your worms with proper ventilation, a moist – but not too wet – bedding source (such as shredded newspaper) and food. Keep their habitat in a temperature regulated space, moist, and with an adequate supply of tasty scraps and an initial colony of worms will increase to perhaps double in 3 months and quadruple in 6 months.
Harvesting your castings is simple. When the bedding has darkened, looking more like soil than the newspaper or other material used, it is time to harvest. To do so, add new moist bedding material and kitchen scraps to the opposite side of the habitat and stop adding food to the side with all of the castings. The worms will migrate to the side with the food on it – usually in a few days. You can then harvest your castings. When the new area fills ups, repeat the process and you will have a steady supply of new compost for your plants.
Photos by Terry Pellegrini.
Sources
About Worm Castings - https://ucanr.edu/sites/mgfresno/files/262372.pdf
Red Wiggler – http://bioweb.uwlax.edu/bio203/2010/yard_jose/
California Master Gardener Handbook, Second Edition, Page(s) 56-57