compost bins

Reworking our Aerobins

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One of our two Aerobins, alongside our worm farm
One of our two Aerobins, alongside our worm farm

At present, we have three Aerobins and one worm farm. The thing that makes the Aerobins special is the  patented lung ® or aeration core inside. This is a series of connected pieces that provides greater levels of circulation, and therefore faster decomposition.

The pieces of the Aerobin "lung", mangled through use.
The pieces of the Aerobin “lung”, mangled through use.


At least, that’s the theory. In practice, the pieces often get mangled when turning over the contents of the Aerobin, and several of my hat-like structures have been damaged beyond use. I know I’m not the only one to experience this.

A replacement aeration method, made of out 90mm pipe
A replacement aeration method, made of out 90mm pipe

Taking a suggestion from my dad, I emptied out each of the Aerobins, and removed the aeration core pieces. To replace this, I drilled holes in a length of 90mm polypipe, adding a cap on the end. (These are standard plumbing items that can be obtained from the nearest hardware or plumbing store.)

The result is a more robust source of air circulation, that should be resilient against day-to-day use. Touch wood, it should still give me the faster aerobic breakdown of compost.

The Aerobin refilled, with its new home-made air spike
The Aerobin refilled, with its new home-made air spike

Finally, we have a proper compost heap

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A proper compost heap, out the back
A proper compost heap, out the back

For a long time now, we’ve had two compost bins (Aerobins) and a worm farm. Which have been great, particularly after I gave them more solid foundations to sit on.

That still left me with a hankering for a proper compost heap, to supply organic material for our guerilla-gardened food forest.

Some space has finally opened up at the back, giving the me opportunity to construct the first of several compost bays (at least, that’s the plan).

Creating a square metre of compostable material wasn’t hard, between the piles of fallen leaves, weeds galore, and other green materials. I’ve turned it once already, and it’s starting to build up some heat.

Onwards to compost!

A wheelbarrow full of coffee grounds

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A wheelbarrow full of coffee.
A wheelbarrow full of coffee.

It’s not every day that you end up with a wheelbarrow full of used coffee grounds, but I’m looking forward to making it a regular occurance at Lewisham House.

A little while back, a new cafe opened up just down the road, The Pig & Pastry. Other than their passion for great food, they also have a real interest in environmental issues. This includes some lovely raised garden beds set up in their backyard, for vegetables and herbs.

A week ago I approached them with a strange question: “what do you do with your used coffee grounds?”. Nothing as it turns out!

Coffee grounds are much loved in the permaculture community, as a source of free fertiliser for the garden. Apparently they deter (or hopefully kill?) slugs and snails, and the grounds are a particular favourite of citrus trees.

Online there are a number of long conversations about the relative merit of coffee grounds, including whether they’re too acid, and their effect on chickens. The general consensus is that when they break down, they become more neutral, and they don’t appear to be too toxic for chickens.

So I’ve left several plastic buckets down at the cafe, and I’ll drop down every week with a wheelbarrow to pick up the grounds. This saves them rubbish fees, and keeps my compost bins happy. A win all round!

Choosing the right inner-city compost solution

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A little while back, a very good friend of mine approached me with a simple question:

What compost bin should he choose for their household?

While it’s a simple question to ask, there are many possible “right” answers, depending on the circumstances.

This post outlines a few of the options, and explores how the decision was made.

The situation at hand

  • Classic two-parent, two-kid family, with both kids still quite young.
  • Located in inner-west Sydney, living in a free-standing house on a fair-sized block of land.
  • Due to the demands of the kids, there is no time for either adult to garden, beyond a few pots of hardy herbs.
  • Existing ornamental garden beds and a number of trees, as well as areas of grass.
  • A single lemon tree of some age, not well fed and producing few lemons.
  • A general interest in “saving the environment”, but are pragmatic about what they realistically have time for.

So, what composting solution would fit?

Option 1: full-sized compost bin

One of our two Aerobins, alongside our worm farm
One of our two Aerobins, alongside our worm farm

The classic composting solution is, well, a compost bin. The idea is simple enough: you put a mix of “green” and “brown” material into the bin, keep it moist, and give it time. In due course, it decomposes down to rich compost that can be used in the garden.

There are many options, from fancy (and expensive) Aerobins, all the way down to simple one-piece bins with a lid. The advantage of fancier options is typically two-fold: they claim to decompose the scraps quicker, and they typically give easier access to the compost without having to wait for the whole bin to compost down.

One of the challenges for compost bins, however, is that they work best when full. Ideally, “hot composting” involves at least a cubic metre of material, making it less suitable to top-up-as-you-go situations.

And in this situation, there is the one big problem: what to do with the compost?

It’s all very well to be creating lovely compost, but without a vege patch, what’s it needed for? The decorative garden beds would benefit from the compost, but not to the extent that you’d go to the year-long effort of running a compost bin.

Option 2: worm farm

On the surface, worm farms are very similar to compost bins, but they work on quite different principles. Instead of composting via bacterial processes, worm farms use … worms … to break down scraps.

The worms are regularly fed of things such as kitchen scraps, which they munch through to create vermicast (worm castings) and “worm tea” (liquid fertiliser). This is truly wonderful stuff, which plants love.

There are an incredible range of worm farms of every size and shape, each suited to a different circumstance. Worm farms thrive on small, regular feeds which is a good match for a household’s worth of kitchen scraps.

Care, however, needs to be taken about what goes into the worm farm (no citrus or onion, for example). And again the big problem: what to do with the output of the worm farm?

Option 3: in-ground composting

A "Little Rotter" in-ground compost bin, in one of our garden beds
A “Little Rotter” in-ground compost bin, in one of our garden beds

The last option considered was an “in-ground composting”. This comes in many forms, from the “Little Rotter” compost bin shown above, through to a simple length of pipe embedded into the ground (the favourite approach of permaculture folks).

In all cases, the principle is the same. Drop kitchen scraps into a container that’s embedded into the ground and open at the bottom. The worms that naturally live in the garden are attracted to the scraps, which they munch through. The nutrients then leach into the surrounding soil.

(My grandma still uses the simplest version of this approach: dig a small hole in the ground, drop in the scraps, cover it back over with soil. Her vege patch results speak for themselves!)

In the end, the in-ground composting was the chosen option.

The lemon tree was the key: by placing a number of in-ground compost bins around the drip line of the tree, kitchen scraps could find a better purpose, and the lemon tree would thrive as a result. With the in-ground option, there was also no upkeep or pressure, and it’s well suited to regular small feeds.

Your mileage will vary

In all cases, the natural processes of composting work best when they’re in sync with the human processes of the household. And bigger (and more complex) isn’t necessarily better!

So there isn’t one right solution, only the solution that best fits the circumstances.

Happy composting!

So much for compostable cutlery

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Yes, that’s a pair of “biodegradable” knives in the compost.

Our housewarming was in April this year, and we had a pile of family and friends turn up on the day. In keeping with our eco-renovation, we sought out environmentally-friendly plates and cutlery.

The plates were easy: paper plates that we could confidently compost afterwards, adding valuable “brown matter” to our compost bins. As for the cutlery, we chose disposable items that were clearly marked as “biodegradable”, with specific instructions to compost once used. They looked like normal plastic cutlery, but cost somewhat more.

So great, let’s test that claim! As the party wound down, we asked guests to deposit the paper plates, food scraps and yes — cutlery — directly into the compost bin. A week later, that was covered over with a pile of fresh poultry poo, from our chickens.

Within a week, the compost bin was steaming hot, so was obviously working well, all thanks to the chickens.

Fast forward six months, and it’s time to use the compost when preparing beds for summer. So I crack open the compost bin, as shown in the photo above.

The plates: completely vanished, along with all the food scraps, to make wonderful compost.

The cutlery: as shiny as the day we bought them 😦

Now don’t get me wrong: this didn’t surprise us at all. The claims on the packet of cutlery seemed completely implausible, but what better way to test it.

More seriously, this highlights the problem with a lot of these “green washing” claims. Ok, they’re “biodegradable”. So does that mean they’ll break down in a home compost bin in 6 months, or does it require 5 years in a council tip, when it then breaks down to … what?

So yet another black mark for manufacturers for truth in advertising. (And before you ask, we had too many people to use our own reusable metal cutlery, which clearly would’ve been the best eco option.)

Details on our eco-kitchen

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Key elements of our eco-kitchen (click to see larger version)

Our kitchen has ended up a little out of the ordinary. Starting from a clear focus on low chemical use and simple materials, we’ve made a few decisions that might be interesting.

The key points on our eco-kitchen:

  • We’ve completely avoided using melamine-covered particleboard (“whiteboard“), as this  emits huge amounts of volatile organic chemicals (VOCs), is considered industrial waste when the kitchen is taken apart, and can’t be recycled. This is truly nasty stuff.
  • Instead, we used an E0 FSC-certified birch eco-ply from Finland (of all places!). “E0” indicates the lowest level of VOC emissions, and this ply has every certification going. It’s also a truly beautiful material.
  • The inside of the cupboards are protected with shellac, a lot friendlier than many of the artificial sealants.
  • The benchtops are unsealed solid kauri, with experience in other kitchens showing that while they wear and mark over time, ongoing gentle cleaning keeps them looking beautiful.
  • The cupboard fronts are solid kauri, painted with low-VOC Haymes paints (no two-pac polyurethane coatings here!). In addition to being much better for the environment, the semi-gloss paint gives a much softer and warmer feel to the kitchen.
  • The walls and ceilings are also painted with low-VOC Haymes paints.
  • The floors are solid kauri floorboards, with a tung oil finish (no polyurethane finishes again).
  • LED lights are used throughout, including the downlights in the ceiling and the strip lighting under the upper cupboards.
  • The large servery window (which can be opened onto the deck) and the upper window behind the cooktop both bring in lots of natural light, reducing the need for artificial lighting.
  • The moving glass is double-glazed, while the fixed glass is triple glazed.
  • The fridge (brought from our old house) was purchased as the only 5-star efficient fridge at the time, slashing our electricity bills.
  • There is an under-floor vent beneath the fridge to draw in cool air (increasing efficiency by up to 20%), with a wall vent that goes into the pantry cool cupboard (more on this in a future post).
  • We chose a water and energy efficient Miele dishwasher, installed new as part of the fitout.
  • We have an on-bench compost bin, collecting scraps for the big compost bins and worm farms outside. There is also a recycling bin inside one of the cupboards.
  • There’s a walk-in pantry beside the kitchen, which is cool and dark (also to be covered in a future post).

We love the kitchen, and it’s both practical and beautiful (we think).

As it turned out, commercial kitchen companies couldn’t cope at all with our requirements. So we had it made by a local craftsman, Ian Thomson (see his website for more on this work).

While it isn’t a cheap option by any means, we’d highly recommend going down the route of a bespoke kitchen, as it gives the time and opportunity to really refine what will be delivered.