Carbon storage on a backyard scale

Backyard gardens accumulate old timber, typically from trees that have blown down or been cut down during pruning, plus building timber so old that its value for construction has become outweighed by the fact that it is taking up valuable space and looks ugly to boot.

The wood heap in our garden grows for some years until other pressures force me to deal with it. This Spring, a long chain of causality has pressured me, once again, to get out the chain saw and table saw to sort the wood heap onto the firewood stack or the kindling stack. [In brief, to be able to find working space in my own shed, I have to move the woodheap to make room for a new chicken shed so that I can empty the old chicken shed to receive a bunch of unused furniture that’s clogging up my shed. So it goes – each job in a garden generates six others!]

My youngest son is kind enough to help Dad with this work, and cook and gardener move all that wood by wheelbarrow around the property until, finally, space is cleared.

Now all that has to happen is the building of the new chicken shed, the movement of stuff hither and yon until space and order appear in front of my workbench, and the other piles of carbon – two very large stacks of twigs-and-sticks – get put through the shredder and laid onto the soil of the garden paths to break down further for storage in the soil as worm food.

The soil of this district is a sticky red clay; in my garden, the rich loamy black texture of the soil arises from annual storage of carbon broken down from mulch, shreddings and compost, seasoned with the ash from our winter wood-fires.

Spring mulching

At the end of winter, below-average rainfall and unseasonably hot weather have combined to push the panic-button on capturing the last rainfall events in the soil before the eight months of dry weather are upon us. The main rainwater tanks are full, so now I need to lock down twice that volume of water in the ‘big brown tank’ that is the garden itself; this is done by mulching the surface under a thick layer of friable straw.

So all the fun of planting out Spring seeds and seedlings goes on hold, and the winter stores of barley straw – laid down in autumn on the paths and since worked over thoroughly by the chickens and watered by winter rainfall – is moved into the orchard under the burgeoning green of the table grapes, peaches and raspberries. Other beds will be mulched in similar fashion over the coming weeks.

Simply covering the soil in this way is worth the original cost of the straw three times over; mulch reduces the water bill and adds to the nutritional stores of carbon in our soils.

Somewhere in the next decade, I’ll get out of the work force and will be looking to these same soils to feed both cook and gardener for a further twenty years. Such wonderfully warm and rich organic soils can’t be trucked in; they need to be created in-situ over the span of at least a decade.

Mulch has additional benefits. It encourages earth worms to work up to the moist cool surface of the soil just below the mulch, and to mix this organic matter deeper down. The wormholes left behind (called ‘macropores’) allow the soil to breathe and roots to find their way deeper down, giving our fruit and vegetable crops added resilience when the hot weather comes.

Growing almonds on a grand scale

Having been born into a landless city-based family with a gift for engineering, rather than a farming family with a bunch of acres to bequeath me, has meant that my home garden stands in lonely stead for the life I would have loved to have led on the land.

But honest introspection forces me to admit that I probably would have made a lousy farmer, spending all my time in the shed trying to invent a better plough, rather than being out there doing the ploughing that was needed.

Still, its that love of growing plants that has shaped my professional career, and I’ve become that guy who builds measurement tools for farmers.

And so it was that my latest efforts took me many hundreds of kilometres down the Murray Valley Highway into the vast commercial almond orchards of western Victoria. Here, almonds are grown on a grand scale – this single property grows only almonds, over an area of 1200 hectares (3000 acres).

Driving for many kilometres through stands of blooming almond trees in the last days of an Australian winter made the long trip down worthwhile.

But for sheer scale, the piles of almond shells stacked up outside the almond processing plant took the cake. Giant trucks and earthmoving equipment, plus conveyor-fed stock-piles, gave some sense of just how many almonds are produced over this vast area.

These almond shells are spread back on top of the local soils to improve organic matter or processed further into cattle feed or compost.

I clammed up and didn’t mention to a soul my single ancient almond tree at home in our kitchen garden.

Father’s Day Harvest

Down here in southern Australia, the first day of Spring (1st of September) fell on Father’s Day, and the sun shone over our warm garden. Crops planted last autumn and grown over winter are producing at last, and all those weeks of wet weeding seem suddenly worthwhile.

The asparagus is shooting and there’s lettuce aplenty for salads, to which we add nasturtium flowers for colour and piquancy and slices of yellow capsicums (peppers) that were planted a year ago. These have survived the mild winter frosts of the Adelaide plains and are bearing fruit that they’ve carried through the winter.

The cook’s skipping about the place harvesting stuff for bottling – red Russian kale, purple sprouting broccoli, the first broad beans, beetroot for kvass, Daikon radish and fielderspitzkraut cabbage for sauerkraut and kimchee.

Nor is the gardener unhappy – he’s breathing a sigh of relief that the Lady Finger banana palms felled in late winter (to cut the pathway for possums from local trees to house roof) have ripened satisfactorily in their shiny blue and silver ‘banana-ripening’ bags. The stern eye of the cook has beamed away elsewhere…