A lot of the specific information about worms and setting up your worm bin has been gleaned from our own first attempt at vermicomposting and from the “Worm Lady”, Mary Appelhof, and her amazing book “Worms Eat My Garbage”. Mary Appelhof self-published this book in 1982 and continued to publish her own guides to gardening and sustainable living – eventually growing a small publishing company of her own. She passed away in 2005 but her company still exists and publishes her guides and can be found via this website: Flowerfield Enterprises.
We’ve had a worm bin in our basement for about a year now (they do need to stay in a relatively warm environment, so there’s no hiding them out in the backyard over winter if you live in Calgary!) and they’ve been doing pretty well so far. The worms were a surprise gift from Momma innercityfarmer so, while we had been talking about vermicomposting at that point, it was perhaps the best possible incentive to start right then!
the little red wiggler
The type of worm most often used in vermicomposting is the red wiggler, the Eisenia foetida. Redworms are more efficient than the common earthworm at breaking down food waste, so if you’re planning to use the worms for your kitchen scraps, these guys are the ones you want for sure. In fact, a kilo of redworms could go through approximately half a kilo of food waste per day!
You can put worms in almost any kind of container. One that is more shallow than deep is generally better because worms are surface feeders and you want the compost, bedding materials, castings and worms to be in a loosely packed environment that has a lot of air spaces. The bedding materials can be made out of shredded paper, newspaper, corrugated cardboard or peat moss – any substrate material that the worms can live in. It needs to be quite moist (about 75% moisture content) as the worms are 70 – 90% water themselves and they need a wet environment in which to breathe.
You’ll want to nest one bin inside the other and poke tiny holes in the bottom of the inner bin to allow some of this moisture to drain out of the bottom as “worm tea”. There probably won’t be too much liquid (especially in dry Calgary, we often do not have any), but you don’t want it to pool in the bottom of their bin either.
According to Mary Appelhof, the secret to keeping your worm bin from getting stinky is to make sure that the bedding materials don’t get packed down. Vermicomposting is an aerobic process; the worms need plenty of air and oxygen to digest food, and it isn’t until you get highly compacted compost that starts breaking down via anaerobic bacteria that you will get bad odours.
Almost all of your food scraps can go into the worm bin – vegetable waste, plate scrapings, egg shells, sauces, tea bags (with the staple removed), coffee grounds and filters, even things that have spoiled in your fridge can go into the bin. Technically you can even put meat and bones into the bins (the bones will get picked clean) but you are increasing your chances of things getting smelly. The only major no-nos for the worm bin are obviously anything that doesn’t break down – glass, plastics, metals or rubber bands. We have been feeding the worms just vegetable scraps so far and it seems to be working. Perhaps when we’ve had them for a while and we have a growing worm box, we’ll get a little more adventurous with their food.
The worms need very little care or attention, all you have to do is feed them fairly regularly and replace the bedding materials every so often once the bin is full is full of castings. You want to bury the food throughout the bin when you feed them and put the scraps in different spots each time. You don’t have to feed the worms every day and, even if you go on holidays for two weeks, you shouldn’t have to worry about them. A month is probably the longest you would want to go without feeding them.
One trick we have for our compost that we do for all of our food scraps, whether for the outdoor compost or the worms, is to keep an ice-cream pail in the freezer in which to put everything. It keeps the kitchen from smelling or having to deal with a squishy compost pail and any fruit fly eggs will be killed in the freezer. We just have to make sure we thaw out our food scraps before feeding the worms.
One anecdote I’d like to share from Mary Appelhof’s book is about germinating avocado pits:
“Have you ever tried to germinate an avocado pit? Have you tried the trick with the three toothpicks, inserting them around the diameter of the pit, placing it on top of a jar of water, and keeping it watered for … well, months? Until you either got tired of it, or it finally did sprout?
Well, have we got a deal for you. Throw your pits in your worm bin, cover, and forget about them. That’s all. In time – it may take months, but it’ll happen – you will find a ap root coming out of the bottom, and a sprout coming out of the top. When this happens, transfer it to a pot. One winter nine out of ten avocado pits I tried this way germinated. I now have more avocado plants than I know what to do with – in the living room, on the front porch, on the side porch, in my office… You, too, can be the first on your block to be a success with your avocado pits.”
worm castings for your garden
Vermicompost is organic matter that has been processed by worms and can be used to augment your garden soil. When the compost is completely digesting by the worms, you are left with worm castings. Castings look just like dark topsoil and have no smell. They can be pretty wet and you can add them to your garden just like you would top-dress with a good compost or fertilizer.
You have to be a little bit careful because the castings are a very highly concentrated nutrient. All of the carbon in the compost will have been digested by the worms – released as carbon dioxide – and what is left is phosphorus, potassium, calcium and magnesium in the form of salts. These salts make fantastic fertilizers when diluted a bit, but when put on plants in a high concentration can be hard on them.
The castings can be mixed with potting soil and used for starting seedlings, sprinkled on top of houseplants or added as a top-dressing to your outdoor garden plants. Or, you could try making a batch of…
Compost tea is a liquid alternative to conventional fertilizers that can be sprayed on your garden plants (veggies and flowers) to develop stronger and healthier plants with a better root structure. There are a bunch of different types of compost teas that you can make using different materials (nettles or other organics, worm castings) and different mechanisms to draw out the beneficial micro-organisms (aeration, fermentation). The benefits of compost tea include (from Worms @ Work, based in Calgary, Alberta):
- A source of foliar and soil organic nutrients.
- Chelated micronutrients for easy plant absorption.
- Nutrients in biologically available form for both and plant and microbial uptake.
- Competes with disease causing microbes.
- Degrades toxic pesticides and or other chemicals.
- Produces plant growth hormones.
- Mineralizes available nutrients for plants.
- Fixes nitrogen.
When using worm castings, it’s recommended to have an aerated system. You could do this with a little pump similar to what you would put in an aquarium, but, not having one on hand, we will probably try a bit of a fermentation period (5 – 7 days?) and see if we get a good effect.
the ‘ick’ factor
So, worms are gross. I can go on and on (and have!) about the benefits of vermicomposting, but the bottom line is that worm are gross and I don’t like to touch them. Usually, all worm-related activities (feeding, replacing bedding material, harvesting castings, etc.) are the job of the other innercityfarmer in the household. Then came the sunny day in March that I wanted to start some seeds indoors and use some castings to augment our otherwise bland potting soil mix. Being the only one around, I decided that I had better face my
fear, disgust, fear of the worms and get the job done.
The nice thing about the worms is that they don’t want to be out and about anymore than you would like them to be. They don’t like bright light or heat or any of the lovely bits of the sunny day on which I chose to work with them… so they bury themselves deeper into the compost. You can use your hands or a spoon or whatever to pull bits of compost off of the top of the pile and the worms just keep heading south into the cool and dark places at the bottom of the pail. I scooped out a half bucketful of worms and compost and put it into a large, shallow bin, so that I could push the de-wormed castings to once side and build up the pile of worms on the other. Once I had removed a lot of the compost and noticed that what remained was getting very very very concentrated with worms, I cut my losses and returned them to the larger bucket. Worm-free castings and compost for me without having to actually touch the worms.
I imagine there are much faster ways of harvesting your worms (picking them out by hand or using a screen to sieve the compost) but for the small amount I needed for my seedling pots, this seemed to work alright.
I’d like to tell you that after this experience I am much more comfortable with the worms, but no, they really are pretty icky. Awesome, but icky.
If you want to start a worm bin in Calgary, there are a couple of great groups that have all of the materials and the worms you would need to get started – you can even buy purpose-built worm bins, though nesting hard plastic containers of any sort will do just fine. Check out Worms @ Work (who often visit the local farmer’s markets around Calgary to show people what it’s all about) or Green Calgary who have the bins and bags of castings available in their store, with worms being delivered on certain days.