Vermicomposting: How a DIY worm farm can compost food scraps, paper or a whole kangaroo

Worms. I’ve got a few.

I split my time between a small inner-city apartment in Sydney, Australia, and a piece of wild land that was once a farm, abandoned in the 1970s, located four hours to the south.

These two places are quite different – one is filled with the constant noise of city life, while the other echoes with the sounds of the wilderness: kookaburras, cicadas, and, at night, owl hoots and the eerie calls of brushtail possums. Yet, both have something in common: a thriving worm farm. The farm’s worm setup is large enough to handle waste from the entire household, whereas the one in the city is compact, fitting on a porch and simple enough for anyone to manage.

On the farm, I let the land follow its natural course, providing a peaceful retreat. Underground, however, is a bustling hub. Inside a 4000-litre tank buried on the property, a vast worm colony processes all my sewage and grey water, transforming it into nutrient-rich liquid and castings. These are slowly released through a series of infilled trenches and then absorbed by the surrounding forest soil.

The giant worm farm in the wilderness is covered and allows for some dietary variation, beyond the regular toilet waste and shower water, by adding compost, weeds, or even animal carcasses found on the property. My guiding principle is that anything once living finds its final resting place in the worm farm.

Whenever I open the lid and peer into the dark void of decomposition, I’m amazed by the rapid disappearance of whatever is placed inside. A 50-kilogram male eastern grey kangaroo (Macropus giganteus) is nearly unrecognizable after a week and completely gone after a month. The worm farm has evolved into a diverse ecosystem, with frogs, spiders, and fly larvae thriving in the nutrient-rich environment akin to the Daintree Rainforest.

Despite more than eight years of serving as a repository for all things organic, and countless wheelbarrows of material shoveled into it, the worm farm never fills beyond a quarter. No matter how decayed a kangaroo or bird may be when added, there has never been any foul odor. This operation is far from amateur; local shire council inspections every couple of years ensure compliance.

When the worm farm was installed in 2018, I had the chance to ceremoniously introduce the worms to their new home – a small bag of tiger worms (Eisenia fetida), a species recognized globally for composting prowess since being named in Europe in 1826.

Brandling worms (Eisenia fetida). These annelid worms are used by gardeners to speed up the decomposition of organic matter (particularly food waste) in compost heaps.

Independent earthworm researcher Robert Blakemore notes that this species thrives in temperatures ranging from -2˚C to 40˚C and can endure losing nearly two-thirds of their body moisture, as well as full water immersion for up to six months. He emphasizes that no other species offers such significant benefits to humanity, with a compost worm reportedly capable of processing its body weight in waste each day. It’s no surprise then that a dead kangaroo can vanish in a few weeks.

Everything placed in the worm farm is broken down into its basic components by the worms and gradually absorbed by an ancient red gum forest, enriching the ecosystem. To me, the worm farm is like a gateway to immortality, where all life is recycled. I often tell my children that when I pass, I wish to be placed there, joining the cycle of life. The thought of being cremated and kept as anonymous ashes in a jar does not appeal to me.

I have a faithful chocolate border collie who shadows me like a personal security detail. The greatest honor I can give him is to pass through the worm farm when his time comes, ensuring he remains close to me. My daughter, however, is not fond of this idea for our family dog.

Urban worm farming

When I started spending part-time in the city, I brought with me a bag of tiger worms from the rural worm farm to seed a small, commercially made compost container in my courtyard.

This small urban worm farm is more immediate and engaging than the large one. It measures about half a meter in diameter and height, with several vertically stacked bins that can be rotated when full.

In contrast to the rural setup, where the worms are deep in a large tank, the city worms are easily visible and fascinating to observe. Sometimes, I find myself gazing at it, intrigued by the unsightly yet mesmerizing decomposition process.

Much like nobody wants to see how a sausage is made, decomposition is not a pretty sight. When I lift the lid of my urban worm farm, a tangle of wriggling worms greets me. There are so many that it seems like they could devour my hand in minutes if I plunged it into the decaying organic matter.

Into my apartment worm farm goes everything organic: vegetable scraps, dog waste, dog hair (my dog sheds a lot), eggshells, bills, tea leaves, coffee grounds. Upon seeing a picture of my worm farm, Blakemore expressed slight concern over my relaxed approach.

Blakemore advises, “Eggshells should be crushed or microwaved to aid decomposition, although they will eventually break down.” He adds, “Ditto for fur. My bane is teabags; they seem to be made of plastic as they don’t decay! Also, those silly labels on bananas or avocados.”

He also warns, “Dog waste can carry parasites, but worms can stabilize many of them.”

No matter how much I add to my urban compost, the worms keep up. Eventually, after many months, I must rotate the bins, moving the full one to the bottom to start anew. By then, the contents of the first bin will have transformed into rich black soil, ready for my courtyard plants.

This cycle of life highlights that decomposition is a stark reminder of mortality, and we inhabit a world where everything consumes everything else. Soil’s humble worms are the facilitators of immortality, processing all that once lived.

I recall Blakemore’s statement: “Everyone should compost. There is no reason not to, except for our major sins of ignorance and laziness.”

What to consider if you would like to start your own worm farm:

Compost worms are readily available commercially – the tiger worm (Eisenia fetida), originally from Europe, is now found globally. While worms can be purchased easily, I’ve shared “starter” colonies with friends – just a small bag of worms – and within weeks, their bins were flourishing!

You’ll be amazed at how much waste a worm colony can process, even in a compact urban worm farm. They are easy to set up and purchase. However, if you need a system for handling a household’s entire waste, you’ll require professional installation and ample space.

I keep my urban worm farm out of direct sunlight. Choose a shaded spot if you live in a warm climate. It also doesn’t produce odors – although lifting the lid resembles a horror scene, it is not unpleasant to have nearby.

Composting utility bills and junk mail is a favorite of mine. (Avoid heavily colored or glossy papers.) There’s a unique satisfaction in turning undesirable items into dirt within a week!

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Urban worm farming What to consider if you would like to start your own worm farm: