cooking compost and cicadas

If it seems that compost occupies my thoughts to a greater extent than say . . . yours – it’s because I’m looking after 10 bins at present. Five are our own, three are in our new shared kitchen-garden at Sue’s place, and the last two belong to the holiday house whose pool and garden I tend. Each one gets fed different stuff, cooks at different temperatures, takes different times to finish. And has different inhabitants . . .

These are cicada larvae (we think – I’ve put a few in a clear plastic container, and we’ll see what emerges . . . ). There are scores of them in our slow, cool, old compost bins. And when I mused aloud about their nutritional potential and how some cultures might drool over such a handfull, Mary (the unseen, unsung and Indespensible Gardener) suggested I entitle the photo :  ‘Grub’ . . .

There are few creatures that can survive a freshly-fuelled, well-mixed compost pile. For it to do its job of killing off mauvaises herbes and herbes persistantes, and wild seeds and pathogens – then temperatures of between 130 and 170 F. ( 57 – 77 C.) are needed. Higher than this and our friends the microbes take a vacation to cooler climes, or die in their trillions. Some concerned gardeners would rather not be part of such wholesale massacres, and only do long slow cool compost cooking. ‘A chacun, son goût’ – which actually means : I think they’re unscientific wimps. High combustion will indeed wipe out vast civilisations of microbes, as will washing your hands before eating, or boiling your kettle for a cup of tea.

Fortunately, this high-burn period of compost alchemy doesn’t last for ever, and new civilisations are soon happy to make the epic trek back to the centre of your personal Chernobyl, from the outer edges of your bin whence they fled when their own particular global warming got unbearable. Microbes, better than humans, can cope with these temporary discomforts. They are, after all, us. Just in a smaller, more adaptable form.

Size matters. The size that humans are, and the discovery/necessity of fire are intimately linked. If humans had evolved smaller – say mouse size – their need for fire would have resulted in tiny, precarious bonfires of straw and twigs – easily blown away or blown out by the the slightest wind. Humans upped to the size of mastodons would have had enough bulk to keep warm – without fire. The need/invention of fire was a result of our finely-balanced/pure-chance size : not big enough to provide our own heat, but smart enough to make heat for our skinny little bodies . . .

Well, so it is with compost heaps. There’s an optimum size, and the only sure way of cooling your heap is to reduce its bulk. Three foot cubic will get it cooking – two foot will cool it. The previous post showed me turning a cooling pile, and adding water (and of course air). The temperature dropped through the floor. For a day.

I went back there today with our room thermometer, which was showing a comfortable 27 C. as I walked across the village. Flip open the pile, and just a few inches under, the mercury shot off the scale : heading towards 77 C. and total genocide. There are months to go – and several turnings – before this lot ever gets near a plant. Going by my previous piles, each bin should be a writhing mass of slithery creatures, partying in a sweet-scented, crumbly black heap.

When the war is over, and the thermo-nuclear event has passed, in will come the creepies, and the crawlies, and our friends – the worms.

Now for the academic cavalry, courtesy of Google, and Washington State University :

“In aerobic composting proper temperature is important. Heat is released in the process. Since composting material has relatively good insulation properties, a composting mass large enough (3’ x 3’ or 3 x 3 metres ) will retain the heat of the exthermo-biological reaction and high temperatures will develop.

High temperatures are essential for destruction of pathogenic organisms and undesirable weed seeds. Also, decomposition is more rapid in the thermophilic temperature range. The optimum temperature range is 135° -160° Fahrenheit. Since few thermophilic organisms actively carry on decomposition above 160° F, it is undesirable to have temperatures above this for extended periods.

Eggs of parasites, cysts and flies have survived in compost stacks for days when the temperature in the interior of the stack is around 135° F. Since a higher temperature can be readily maintained during a large part of the active composting period, all the material should be subjected to a temperature of at least 150° F for safety.

Sometimes compost operators avoid prolonged high temperatures because the nitrogen loss is greater at high temperatures because ammonia vaporizes, which takes place when the C:N ratio is low. But there are other ways of minimizing nitrogen loss than operating at a lower temperature. The advantages of destroying pathogenic organisms and weed seeds, controlling flies, and providing better decomposition outweigh any small nitrogen loss due to high temperatures.

A drop in temperature in the compost pile before material is stabilized can mean that the pile is becoming anaerobic and should be aerated. High temperatures do not persist when the pile becomes anaerobic. The temperature curve for different parts of the pile varies somewhat with the size of the pile, the ambient (surrounding) temperature, the moisture content, the degree of aeration, and the character of the composting material. To maintain high temperatures during decomposition, compost must be aerobic. The size of the compost pile or windrow may be increased to provide higher temperatures in cold weather or decreased to keep the temperatures from becoming too high in warm weather. Experience shows that turning to release the heat of compost piles, which have become so hot (170°-180° F.) that bacterial activity is inhibited, is not very effective. When the material is actively decomposing, the temperature, which falls slightly during turning, will return to the previous level in two or three hours. Also, it is impossible to bring about any significant drop in temperature by watering the material without water logging the mass.

Variations in moisture content between 30% and 75% have little effect on the maximum temperature in the interior of the pile. The initial temperature rises a little more rapidly when the moisture content is 30% to 50% than when it is 70%. Studies show an important and significant correlation between the moisture content and the temperature distribution within the pile. When moisture content is high, temperatures near the surface will be higher, and the high temperature zone will extend nearer to the surface than when the moisture content is low. For example, in experiments at University of California during mild weather when the air temperature fluctuated between 50° and 80° Fahrenheit, the zone of maximum temperature in a pile with a moisture content of 61% extended to within about one inch of the surface while the maximum temperature zone in a pile containing 40% moisture began 6 inches below the surface.

Deeper piles caused higher temperatures and better temperature distribution, and subject more material to a high temperature at any one time. Hence, the actual mass of the material evolving heat is important in providing adequately high temperatures.”

There. Science is so satisfying. Not as much fun as faeries at the bottom of your garden – but in the end, more fascinating.

marking time with compost

We’re waiting on Charles and his tractor to plough le grand potager at Sue’s. I’ve boxes and trays of plantlings that need to go in – watermelons and pumpkins, peas and beans, and 25 sweet corn. But with her L-shaped plot, there’s no point in starting a bed or two as the tractor will not be able to navigate around them effectively. And I do want this serious kitchen-garden prepared properly from the outset. It’s sunny and sheltered and has the potential to be our main provider of food.

But in the meantime, there’s always compost to attend to. After two weeks, the initial combustion has cooled to a hand-bearable 30 C. and the bulk has reduced by a third. Time to turn it all and re-stack it, with the dry outer stuff put in the middle, and the damp ashy material around the outer edge – then a spray of water every five forkfulls. The three bins become two, and eventually one. More space for fresh manure!

I like the work – it’s cookery and alchemy and a visit to the bank, all in one.

This is Big Bin No.1 which has been cooking slowly all winter – today I’m barrowing it the 5 minutes walk acoss the village to Sue’s kitchen-garden.

If I keep up this rate of compost-production, the volume of soil will increase dramatically and it might be sensible to move to a raised-bed system now. It’s not something I’ve done before, and it costs money and time. But I’m not entirely convinced of its benefits. Here in the Midi a kind of raised-bed/ridged plantation is commonplace : the ridge is le billon and the trough or path is le sillon. As I write this, I’m checking the internet for spellings and info – and it’s apparent that there’s lots of experience on this in French, and in the French-speaking colonies. A regional term for it is ‘cultivation en ados’ where ados means a ridge or hump (remember: a dosser is someone who’d rather lie on his back, than do work . . . ).

This is particularly relevant to us, since we too have long periods of drought with intermittent flooding. And as I write I’m becoming more convinced that wood-planked raised beds are alien to this kind of clay terrain, and this climate.

Compost revisited

Excuses, excuses : Work – Christmas – Family – Illness, I have enough excuses to explain away the lack of posts here. My best is this though, borrowed from a Frenchman :-  ‘Eet ees ze Lazeeness!’  – with a Gallic shrug if possible.

The work was intended to provide enough money to enable me to slouch through the bitter end of winter just reading and writing. But the weather has been benevolent, and the worsening state of the world has doubled the urgency of expanding  the kitchen garden. This is from one of LondonBanker’s last blogs:-

Deflation has become inevitable. The bankers, lawmakers, regulators and academics who collaborated in the betrayal still hold power, like the well-armed brigands in the fortress, and their continued collaboration to prevent accountability must inevitably discourage honest savers from risking further loss. Even so, it is the savers/peons who hold the ultimate power as they can starve the brigands. LondonBanker.blogspot.com  Friday, 12 December 2008

I like the idea of starving the brigands – but I don’t see it happening. And first, as a peon [albeit with too much house,  insufficient land and no savings] I must ensure that we don’t starve first.

Time to revisit the compost bins. A post from mid-october shows my carefully constructed wire-and-lino containers, and the plastic bins bought via La Mairie and part-subsidised by our village commune. Another photo shows a heap of compost made last summer.

I had consulted several sources online and I felt confident that with my previous experience I could cook up a good amount much faster this time. The bins were filled with a mix of leaf and strawy horse-manure and remnants of the autumn’s kitchen and garden waste. Plus dosings of my self-generated liquid nitrogen [that's urine] collected over the weeks to act as an accelerator.

So when it came time to undo the mesh and turn it over, I was sorely disappointed to find that little decomposition had occurred. It should have felt like a squeezed-out sponge – instead some layers were too wet, others too dry. And my precious piss had not been able to ignite the process, during the close-to-zero mid-winter months. I had to think again – and start over with a better system if there was to be enough ready for the new beds this spring.

I have reverted to a previous design that worked well enough in the past, but is not quite so neat-looking as the plastic bins [fecked into the background there] and the mesh cages. The pallets came from a building site in the village. The hose is ready to wet the dry leaves.

I reasoned that the pallet-construction gave the heap the greater volume needed to ensure sufficient insulation and combustion. In this last compartment I cut up the lino into 1 metre squares and nailed them to each inside face, to conserve heat and moisture. Each of the four compartments has a front door, hinged with a twist of wire. If compost is to be turned once a month – as recommended for a faster production – then this should make it much easier. As does the four-tined hay-fork I found in a friend’s barn: it’s light and the stuff slips easily off the prongs, where it would tend to stick on the heavier thicker gardening fork. If you’re making lots of compost then even at  40 euros[!] it’s still a good investment. You’re the head chef and alchemist of the garden – and you’re worth it.

There seems to be two schools of thought about whether to put your material directly in contact with the soil – it allows worms access to the heap – or to make a thick latticed bed of sticks beneath the material – to gain aeration. I have alternated with mine – and will report the results. Aeration is vital: an anaerobic compost heap will take 2 or 3 times as long to work -and you can end up with a smelly sludge which has simply rotted – without achieving the temperature needed to kill weeds and seeds, or producing the ‘brown gold’ of crumbly loam.

The other ingredients in the photo above are the milk-bottle of my ‘humanitrogen’ and a 20 kg. bag of sulfate de fer – ferrous sulphate – costing 10 euros from the farmers’ co-op in the village. It was recommended by a village horticulturalist – two handsfull to a bushel of material, particularly if there’s more brown-matter than fresh wet green plant stuff. It releases nitrogen [and promotes lawn growth etc.]I sprinkled it over every barrow-load of mixed-up material that I forked in, giving it all a spray from the hose [the water here is very hard/alkaline] to both dissolve the crystals and get the sponge-consistency.

Finally, I stuck a sharp rod down vertically through the heap to the base, and wiggled it about, and then drove a stake into these holes to make a wider vent-shaft. The compartments were then covered with plastic sacks with the last of the lino over everything to shed rain. Air must be allowed in but not water.

The whole enterprise took up some time – but I hope that I have set up a structure and a system that can run for some years with only the occasional replacement of rotting pallets. The aim is to have one whole year’s compost in hand. Because compost is where a garden begins.

What we are making is additional humus. In soil science, humus means any organic matter which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, if not millennia. The process of “humification” can occur naturally in soil, or in the production of compost. Chemically stable humus is thought to be important to the fertility of soils in both a physical and chemical sense. Physically, it helps the soil retain moisture, and encourages the formation of good soil structure. Chemically, it has many active sites which bind to ions of plant nutrients, making them more available. Humus can be described as the ‘life-force’ of the soil though it is difficult to define it in precise terms; it is a highly complex substance, the full nature of which is still not fully understood. Physically, humus can be differentiated from organic matter in that the latter is rough looking material, with coarse plant remains still visible, while once fully humified it becomes more uniform in appearance (a dark, spongy, jelly-like substance) and amorphous in structure. That is, it has no determinate shape, structure or character.

I think it’s time now to hear from a world-famous horticultural expert :-

“My whole life had been spent waiting for an epiphany, a manifestation of God’s presence, the kind of transcendent, magical experience that lets you see your place in the big picture. And that is what I had with my first compost heap.” Bette Midler [no kidding] New York. 2006