Revenge is a dish best served cold.  Particularly when you are seeking revenge against a tree. Given the pace of their lifestyle, you have to drag it out for those guys to really feel it.

So how better to punish a seed-strewing, bat-choking, weedy cocos palm than – not simply chopping it down – but committing it to a doom of eternal proximity to rotting horse shit?

What a red-letter year it has been for composting.  The year when I discovered the Berkeley method.  It sounds like natural form of contraception and it is hot, but it’s better than that because it works.  Time after time after time.

I have thought I had achieved the giddy heights of hot composting before, long ago when Treasure the white Sussex was queen of the chicken run, freaking me out by regularly supping from my vat of compost tea.

In those days I was convinced that the way to fast, weed free compost was my trusty tumbler,  still the first destination for our kitchen scraps and chookhouse bedding.  The tumbler certainly steams when you crack it open to add the week’s potato peel and apple cores, and not just on these winter mornings.

But I guess, like so many other lovely things, you don’t necessarily know whether you’ve really hot-composted, until you actually experience it  Then you realise that on all those previous occasions when you thought what you were doing was pretty hot, you were wrong, and in reality it was all distinctly tepid.

So what is the Berkeley method of hot composting and how do you get some of that good stuff?

The Berkeley method involves making a big heap of compost – at least a metre tall and a metre wide – all at once, using layers of high nitrogen (“green”) and high carbon (“brown”) ingredients.

I’ve used a a range of different “browns” – liquidambar and bamboo leaves, pine needles, sugar cane hay from the the chook cage (with its own little payload of nitrogenous ordure) and even cardboard boxes ripped up into small pieces.  This is a soothing activity to do in front of television and the only part of compost-making I can get my children have anything to do with).

I usually try to sneak in some partially-rotted “warm” compost from my tumbler as a “green” layer low down in the heap just to keep our household waste systems from being overrun with biomass.  As a small household, we don’t really produce enough veggie scraps all at once to create the bulk materials needed for the Berkeley method.  Other people use thin layers of lawn clipping but we have chooks so we don’t have any need for lawn mowing.  That’s an understatement really – for much of the last three years our backyard has looked like the Somme.

My mainstay for “greens” is, ironically, distinctly brown – vast quantities of equine ordure, acquired at $1 a bag from the horsey country on the other side of the Berowra Waters Ferry.  I’m pretty sure my ten or fifteen bucks, left in an honesty box by the front gate, ends up in the pocket of a shovel-fit teenager, which gives me a warm glow.  You could get the same amount for free in another farm down the road if you had a trailer and good upper body strength.

It’s a fun weekend outing – I particularly enjoy coming back across on the ferry with the windows down, suffusing the palatial surroundings of the marina and its smattering of Hollywood celebrities with the fruity ambience of a stable.

But if your idea of a good time doesn’t involve intimate encounters with 150 kilos of horse manure, there are other options.  Not carnivore poo though.  Just in case you happen to live near a zoo and were thinking of a midnight raid for high nitrogen materials, Robert D. Raabe, Professor of Plant Pathology, Berkeley, in his detailed account of hot composting, reminds us that tiger and lion shit are not worth the effort.

In my first few heaps I also added some wood ash after each layer – it‘s high in potassium, can correct acidic soils and since our wood-burner produces loads of it I’m always trying to think of uses for it.  There’s also a kind of wedding like gaiety to hurling handfuls of white powder over the mountain of poo which I really enjoy.

I think I got a bit carried away on my last batch of compost, though, as I discovered when my youngest did a science experiment: broad beans growing in three different soil types.  My newly made compost was literally off the scale on the Ph test. My vegetables are probably suffering but I suppose at least I now have a convenient lime-rich place for disposing of fresh corpses.

Each layer of your heap should be watered as you build it, til the whole thing is about as damp as a squeezed out sponge.  If it’s especially wet or hot weather you can cover it to stop it from drying out or getting soaked.  As you can see in the piccies above, I roofed my first Berkeley heap with palm fronds, partly to keep my heap from getting too dry and partly just to continue to torment the spirit of the evil tree they were hacked from. None of my subsequent heaps have had a cover, though, and they seemed to turn out just fine.

To be honest, while there are lots of really complicated rules for hot composting – for instance, this article gives a mind bogglingly detailed run down on the carbon-nitrogen ratios of a range of composting materials.  But in my experience, a rough and ready mix of about equal quantities of “greens” and “browns” just seems to work.

Then after you’ve built your heap, you just leave it for about five days.  All the while you are at work – sitting in meetings, shuffling paper or cruelly inflicting post-structuralist theory on innocent undergraduates – that aerobic bacteria is doing its thing.  It’s a curiously comforting thought.

Then you turn your heap.  The aim of Berkeley method hot composting is to create a friendly environment for the right kind of bacteria and fungi – the ones that like plenty of air.  They work quickly, produce plant nutrients like nitrogen, phosphorus, and magnesium and even smell pretty good (trust me on this).  Over the first few days after you build your compost pile, a sequence of different bacteria go to work – first the psychrophilic, then the mesophilic, and finally, once the heap gets to about 37 degrees celcius, the thermophilic.  Once the pile gets up to between 55 and 70 degrees, the heat kills off weed seeds and most insects (and some bacteria too).  But the thermophilic bacteria quickly use up all the degradable materials unless the heap is turned.

But how do you know if your heap is hot enough?  Here’s the advice of one permaculture site: “as an simple guideline. if you can put your arm into the compost up to the elbow, then it is not at 50 degrees Celsius, and is not hot enough”.  If the idea of a forearm coated in hot shit doesn’t appeal to you, you can also use a cake thermometer.  But perhaps not on the same day as the school bake sale.

I don’t bother with thermometers.  After the allotted number of days, I just dig into the guts of the pile. If steam comes pouring out, creating a sort of horse-poo sauna for the shovel wielder, things are cooking.  Best not to turn your heap in your PJs or your ballgown,though.

I’m not so sure about white stuff you can see in the picture on the right. According to the University of Illinois‘ composting boffins, this is actinomycetes – “a higher-form bacteria similar to fungi and molds” which feeds on the woody bits in the pile and helps make well cooked compost smell earthy. Robert Raabe, Dr “Afraid of lion poo”, thinks it’s a good sign in hot compost.  But it usually turns up in an nonaerobic pile so this pic indicates that while my current heap is hot it probably have been turned a bit earlier.

As the old joke says “What’s the difference between a good gardener and a bad gardener? Two weeks”.  Still, with a turn over and a bit of oxygen, I reckon my compost will get back on track. A perfect heap might require that horse do-do up to the elbow but a pretty good heap seems to be manageable without that level of commitment.

My technique for turning the pile is quite primitive – kind of like knocking down a stinky sand castle.  I dig into the steaming centre of the pile, shovel the hottest part of the heap to one side (up against the remains of the tortured ex-cocos palm). Eventually the undercooked layer above caves in in a satisfying way.  I do that a few times, so the outside part of heap is in the middle, ready to heat up again.

Somtimes when I’m tending my compost heap, I feel like I’m channelling the spirit of a brush turkey dad, as he scratches his big pile of mulch around, keeping the temperature just right for his clutch of eggs.

Having turned your heap, you let the heat build up for a couple of days and then you turn it over it all again.  And then again every two days or even once a day if you ever get over-excited. That goes on for about two weeks.  The write up of the Berkley method in the University of California’s Vegetable Research and Information Center (my kind of place) stresses that “outdoor exercise is an added benefit” of hot composting.

For a kayaker, all that shovelling is not bad thing at all, leaving aside the fabulous pile of compost you get at the end of the three weeks of relentless digging.  It’s hot composting and hopefully you get hotter in the process of making it.  Truly, there is no downside.

Some other posts about gardening experiments

My attempts to grow luffa…. no it doesn’t come from the sea!

Night of the living mulch: cover crops for the zombie apocalypse

The ginger family stole my brain!

DIY by subtractions: the kiwifruit arbor

From battery to backyard: the story of our rescue chickens, Dusty, Crumpet and Ruff

Turning our garden into whipbird habitat by making a mess

References

Antonella Anastasi, Giovanna Cristina Varese & Valeria Filipello Marchisio
(2005) Isolation and identification of fungal communities in compost and vermicompost, Mycologia, 97:1, 33-44

Yan Guo, Jinliang Zhang, Changyan Dengand Nengwu Zhu (2012) Spatial Heterogeneity of Bacteria: Evidence from Hot Composts by Culture-independent Analysis Asian-Australian Journal of Animal Science Vol. 25, No. 7 : 1045 – 1054