Compost – moving from art to science

If you have been following our blog for a while, you will realise that composting is a bit of a challenge at Homeland, especially during our super-dry summer, with the compost bins close to some big earth-drying Eucalyptus trees. Even though our second batch of compost has been slightly better, we’ve decided to take it a few steps further. If we want to live and urban-farm more self-sustainable, we have to get thermophilic (hot) composting right.

I basically decided to make good use of the feedback I received from Goshen Watts (from the Geelong Permaculture group) on my previous post, as well as to incorporate learnings I gathered from the AgriSolutions website and a discussion I had with Gerhard Grasser from AgriSolutions.

Assessment

In essence my heaps were too big – both for managing it physically and for managing the temperature and moisture. The greywater pipes running through the heaps made it very difficult to turn them as the fork kept getting stuck in or under the pipes – a total energy blow.

In addition, the material was way too rough to break down in reasonable timeframes. Besides, with the material being so rough, I gather most of the graywater must just have just run through to the bottom anyway.

And so another impromptu project was born “on the fly” – to restructure, reorganise and re-process all the heaps as one massive project. Totally crazy, in terms of effort, but it made sense to do it all as one focussed project.

Inputs

Luckily I could source a lot of corrugated sheets from Gaë, my friendly neighbour who lives in the house at Dreamland. He is absolutely amazing in sharing unused stuff that he has hoarded up – and he has hoarded up a lot over the years! So all I had to buy were the metal posts to keep the sheets in place.

However, I also bought a compost thermometer from AgriSolutions – what an amazingly useful tool if you want to do composting properly! Yes, I know you can stick your hand in there and try and gauge it, and maybe get bitten by some irritated spider or bull ant… But for me it was a no-brainer to splash out a few dollars and do it way more scientifically, over and over and over, especially considering where I was and where I needed to be on my composting journey.

Towers of Hanoi

Next came the big puzzle. In an interesting juggle between splitting and moving the heaps on the one hand, and building the additional partitions and redoing the greywater feeds on the other, over two and a half days of hard labour I managed to restructure the whole area into 6 new bays, each about 1.3m wide, with wind shielding at about 1.8m high at the back and about 1m high in the front. Some of the bays have wind shielding in the back, others just have the old chicken wire that was there before. I only had so many sheets… All the bays have greywater on tap, feeding from the top,  that can be turned on and off as and when needed.

Compost3 - stables

Six compost stables

So I made the heaps much smaller and in the relocation process also mulched the contents much finer. In the end I had our old phase 1 dry “topsoil” in a heap outside the bays, our phase 2 darker compost covered by weed mat in one bay, two bays with fine mulched and wetted material starting the real composting process, a holding bay with rough stuff that must still be mulched fine, and importantly, one open bay into which I can turn any of the fine compost heaps when it’s ready.

Compost3 - bins 3 to 5

Compost bays during construction

Are we there yet?

I was quite disgusted when I used the compost thermometer on the old big heap the first time – it only reached low in the 40°C. Talk about ice cold composting, maybe if I kept on in that vein the weed seeds would have frozen themselves out of action!

So the day after the big project I ran out there with my temperature gauge – we were almost there, clocking in at 50°C. Great was my excitement when three days later we hit the jackpot temperature of 58°C!

Compost3 - jackpot

Jackpot

About a week later, I turned one of the heaps, split it in two, added some new material, added more mulched material from the stockpile and also mulched some of the old material in the heap even finer. The next day, the heap that had the newish material added, clocked in at a record 64°C, while the two older heaps dropped to below 55°C. Time to turn that older heap and maybe add some wet grass clippings I think.

Getting organised

Anyway, I’m now logging all the changes I make, as well as regular temperature measurements. There’s too much on the go to measure the temperature every day, but I try and do it at least twice a week.

Compost3 - log combined

Keeping a log

Happy to report that two of the bins have now been steady at 63-64°C for almost a week. Happiness!

Compost tea

While on the topic of compost, I used to make compost tea in a spare wheelie bin and then spread the foul smelling liquid wherever the trees looked like they needed nourishment most – which is most often the citrus trees.

As part of the compost revamp work, I also acquired a small little solar-powered fish pond aerator through ebay, which I now keep in the compost tea as it does its thing. The aerator is so small, it’s easy to move. Currently I have the little solar panel wired to a stake, but I still want to devise a clamp with which I can just attach it to the wheelie bin’s lid. That will be a fun little time filler project one day.

What a difference the oxygen makes! The tea is now alive and foaming, and it does not smell so foul anymore. It looks and smells fresh and alive. Where it used to be a stinking slog to spread the compost tea, it’s now a pleasure. The second batch is already brewing.

Compost - compost tea

Foaming compost tea

Lessons learnt

Some people get composting right straight away, but I’d venture to say sometimes they’re lucky in that their local climate and circumstances agree more closely with the textbook examples. In our super-dry summer we’ve definitely had to make some adjustments and learn through the process.

Using a temperature gauge helped me tremendously. Previously I was plonking rough materials on a heap and hoping for the best; now it had become a much more informed process.

Mulching the materials finer also made a huge difference. On the one heap it literally chased the temperature up by 10°C just by mulching the materials finer.

I knew you should stir compost tea, but with the bin standing in some remote place where I plan to use the tea next, I never got to stir it. Now with the little aerator, I set the process off and it can take care of itself. If I do weed tea and compost tea in two separate bins, I can even now timeshare the aerator between the two.

 

 

 

About martin@muchmoremulch.blog (87 Articles)
My name is Martin Rennhackkamp, I now live happily in Lara, Victoria, Australia with my wife, two children and two dogs. My interests, apart from the obvious Organic, Biodynamic and Permaculture Gardening and Farming, include sustainable living, surfing, horse-riding, a wide variety of music, dancing, nature, birds, reading, Christianity and a few other things which I never get to...

5 Comments on Compost – moving from art to science

  1. Oh my! That seems like so much work for compost. Ours just gets pilled up unceremoniously and pushed about by the tractor. I really do not know how it works as well as it does. It will be a while before we refine the system.

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  2. Hi Martin,

    Does the electric chipper in the first photo actually work well on both dry and fresh branches, and green material? I’ve read reports on the typical ones from “the big green shed”, just “crushing” most of the material and not turning it into chipped mulch.

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  3. Hi Glenn, I have since got rid of it – it always clogged up with wettish stuff. Before that I had two smaller ones – a chipper and a mulcher (from said shed) – they also didn’t make the grade. For a small house block I guess they would be OK, but at the scale we’re making compost now, they just don’t cope. Not even the red one did. I’ve bit the bullet and got a Hansa C7 from Mowers Galore. It’s a bit dear though. It clogs a bit if there’s too much wet soil on the stuff, but it’s easy to clear – two bolts. But normal wet and dry stuff it works through quite OK. I’ve muched rotten apples, wet weeds, spinach leaves and stalks, all the way to dry pine and eucalyptus branches. Happy so far.

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    • Thanks, I was looking at a similar Honda powered unit from The Red Shed. I’ll avoid “the green shed” electric ones then 🙂

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      • Glenn – sure that makes sense. Just make sure it’s easy to open and clean the inlet and outlet chutes. You don’t want to have to dismantle half the machine to do that – because at some or other stage you are probably going to have to clear those -)

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