Composting With Worms
In this episode we talk about composting with worms or vermicomposting, and how we can reduce our impact on the local landfill while creating ‘black gold’ for our healthy living soil sponge and plants.
Worms and the battle of the stink
Sheri and I visited Rubi the Worm Wrangler‘s place out in Murrieta recently and we learnt how she uses vermicomposting or worm composting to compost the manure from her horses. We were accompanying a group from San Marcos High School’s Future Farmers of America program, looking to use the same techniques in their school farm in San Marcos, CA.
The most impressive thing was that despite having a dozen or more horses, and all their accompanying waste, there was no real smell and very few flies. This is because Rubi uses composting worms or red wrigglers to help her compost down the waste and turn it into highly productive worm castings that she sells at the local farmers markets.
What kind of worms do I use?
So how can we as home gardeners use red wrigglers to help us compost our kitchen scraps to create the perfect ingredient for Healthy Living Soil?
Well let’s first identify the difference between regular earthworms and the composting worm or red wriggler.
A regular earthworm is a tube-shaped, segmented worm. They are commonly found living in soil, feeding on live and dead organic matter. Its digestive system runs through the length of its body. There are many species but in Europe and most of the USA, Lumbricus terrestris is the main one. L. terrestris has the interesting habit of coming to the surface to feed, and then retreating into it’s deep burrow.
Composting worms, or red wigglers (Eisenia fetida), thrive on rotting vegetable matter but are not found in soil. They love dark and damp conditions, but they need oxygen to avoid stinky anaerobic conditions. They are shy creatures who bury themselves when exposed to light. Red wiggler worms can eat about half of their weight in food every day. This means if you put one pound (16 ounces) of worms (about 1,000 worms) into your bin, you will be able to feed them one half of a pound (8 ounces) of food every day. Turning organic wastes into casts takes 22–32 days, depending on density of waste and earthworm maturity.
The great thing about worms is that they tend to multiply when there is more food around, so you don’t have to worry too much about the exact number you start with. Worms can double their population in 60 days.
Composting worms do best in temperature ranges 15-20C (59-68F), yet maximum growth (weight gain) occurs closer to 25C (77F).
Both Sheri and I have worm bins where we compost kitchen waste, and using this method of composting can reduce the amount of waste that ends up in the trash bin by 30-40%.
Where do I buy these fantastic creatures from?
Check out your local area for a reputable worm wrangler, or if you are in San Diego/Orange County go find Rubi at the local farmers market. You can also buy your Red Wriggler Worms online.
How Is It Done?
First the ingredients: the kitchen waste is our fruit and vegetable peels, coffee grounds, tea bags, eggshells, kitchen roll (so long as it doesn’t have cleaning materials or fat on it), in fact most everything but citrus, onions, garlic, dairy, oils, meat and fish.
We have a compost pail by our kitchen sink that is great for collecting it all in.
Diane’s worm bin is one she got many years ago, and it puts everything in one container. Newer worm composterscome in layers, which does help with the harvesting.
Some San Diego residents can purchase worm bins at a discount from The Solana Center.
When the kitchen compost pail gets full, it’s taken out to the worm bin and spread over the top. Next take a handful or two of damp (not soggy) shredded paper and sprinkle over the top. The shredded paper acts as a bedding layer for the worms, and helps to reduce any smells and discourage flies. Once the lid is back on the bin, the worms get to work and do their thing.
About once per year, Diane harvest her ‘worm castings’ – the wonderful highly concentrated, nutrient-packed fertilizer, also known as ‘black gold’.
The harvesting process from a single story bin involves separating out the top 12 inches of worms, food and bedding material (shredded paper) and putting that to one side. The worm castings are emptied out from the bin and use around the yard and in the vegetable bed. Studies have shown that plants ‘fed’ this form of fertilizer do significantly better than those fed with chemical fertilizers. And hopefully you are getting the message by now that those chemical fertilizers are just plain harmful to our healthy soil sponge and plant health.
Harvesting the compost from a multi story bin is a simple as pulling out the lower layer, once the worms have eaten their way through that and migrated up to the second story.
Once the worm castings have been harvested, start over again with a fresh layer of damp shredded paper in the bottom of the worm bin, sprinkle a handful of soil over the top to help the worms digest their food better, put the worms back in, and feed them with fresh food and shredded paper bedding.
The other by-product of vermicomposting is leachate. Some people swear by it as a liquid fertilizer that can be used to water potted plants. Others are sceptical of its benefits. Time for an experiment!
There are lots of ‘do it yourself’ worm bin instructions online. We like this one using two plastic tubs, and this one using nursery flats to recreate a multi story bin. The next level up of worm bin design is what’s known as a ‘flow through’ system – basically a large raised box with a lid. As the compost is created, it drops out of the bottom through a mesh. This gives a continuous flow of compost.
Books and Other References
Regular worms at work – Bioturbation
The Worm Book: The Complete Guide to Gardening and Composting with Worms by Loren Nancarrow and Janet Hogan Taylor
New York Times article – Worms Produce Another Kind Of Gold For Farmers, 2013