I just spent a morning putting together a batch of compost. Four hours of solid work, from getting the green waste that is the basis if this batch to capping it off with a fluffy cap of straw.
The green waste came from a vegetable packing shed, where I had to line up with all the farm utes picking up a load of cattle feed (we’re in a drought, despite the reasonably good rain in the last couple of weeks).
Having heard figures of up to 40% of horticultural production being rejected because it does not meet supermarket specifications for colour, shape, size, etc., I had always imagined that there must be a huge amount of green waste going to landfill from packing sheds. It isn’t true, at least not here in the Lockyer Valley. Some of the big farms that have their own packing sheds also have their own cattle herds, and these get first call on the green waste. The others generally make it available to the public, and from what I’ve seen very little or none goes to landfill. The farmers are eager and grateful to have this source of animal feed.[*see additional note below]
When you think about it, these farm animals are eating better than those of us who shop at supermarkets. Picking of the vegetables commences early in the morning, and the green waste starts coming out of the packing shed around 7.30am. There might be a bit of waste from the previous afternoon in the first few bins, but from then on it is all stuff that has been picked on the same day – and goes straight from there to the farm or, in my case, straight to the composting organisms. If you buy vegetables from the supermarket they have gone from the field to the packing shed, to the market or to the supermarket chain distribution centre, generally on the same day, and from there to the supermarket – you will be getting it two or three days after it was picked if you are lucky.
I have a friend who works in a packing shed who takes pride in the work she does to select, trim and pack the vegetables she works on. When she sees the same vegetables in the local branch of the supermarket her shed supplies her feelings are frequently somewhere between outrage and insult because of the difference in quality she sees compared to when it left her hands.
Anyway, back to the green waste. Lettuce and cauliflower trimmings today, with a bit of broccoli. Two bins are tipped into my trailer by the forklift operator, and I quickly move aside to park and cover my load so others can be served.
Back home, reverse the trailer up to the compost production bins (not easy to do in the tight space between stockpiles of horse manure, poultry manure, chipped tree loppings, chip mulch from our firebreak clearing, and sand/silt from the drains on our two kilometres of access track, as well as the last batch of compost. Set up the water pump and hoses and get out the tools.
Starting the process
The first layer is already in the compost bin: about 20cm of chip mulch from a tree I had to cut out of the firebreak, covered by a layer of the coarse compost materials from the last batch. It’s been lying there under a layer of straw for a week or two, and with the rain we’ve had the composting process in the chip mulch is probably well started. A thick layer of green waste goes on top of that, then a layer of chipped tree loppings that has been stockpiled since last July and is just starting to get fungal strands through the lower parts of the heap.
The mountain of chipped tree loppings from under the power lines. We shared it with one of our neighbours and still got eight trailer loads – a full day’s work to move it all.
I wet that layer thoroughly, before adding more green waste and then a layer of decomposing barley straw from a spoiled bale that I’d put behind the compost bin a while back. That’s wetted down too. More greenwaste and then a layer of months-old broiler droppings. In truth, the broiler droppings were always more wood shavings than manure, with a good dash of spilled feed and water, but now they look decidedly woody.
The growing compost heap, and the chipped tree loppings stockpile in the background
I’m kind of wary of broiler droppings because of the short time the birds are on it, leading to a poor ratio of wood to manure, and not much breaking down of the woody material before I get it. This weathered stuff looks like 80% wood shavings, but I notice that a lot of the woody material is quite soft, and is in a matrix of very fine dark, damp material that might already be compost. Nevertheless, if I was really intent on making 18-day compost I wouldn’t use broiler droppings, weathered or not. But I’m not a great fan of the strict 18-day process. In my experience after 18 days the result can look like compost, but it never smells like it – you know that rich, earthy, good-compost smell? Doesn’t happen for me in 18 days, even when temperatures and moisture content are all perfectly aligned. I wonder how often it happens for others.
What I have seen is that the longer an 18-day compost is left to “mature” the better it gets, with more life in it, and generally after three weeks or so of maturing it suddenly gets that earthy smell like forest litter. From then on it just gets better still, and eventually (if I leave it long enough) has a network of fungal hyphae extending through it. Not that I always leave it to the fungal stage, and at times I start harvesting the finest sieved component before it smells right, if I’m desperate to make some potting mix or a seedling bed.
The last, partly used, batch of compost on the right – covered against the rain over the last few days
Back to today’s compost. From there on it’s just a repetition of the same layers and watering, until the green waste load is used up and the compost bin is full. Then it’s topped off with a thick layer of fluffed up barley straw (to keep it the sun off it while allowing air circulation) and I get out an old tarp to leave beside the bin in case I see heavy rain coming.
Just to make me feel good I measure the dimensions of the heap and take a final photo. Volume of the heap: 2.28 cubic metres. That will drop quickly in the next couple of weeks as the heap settles and water is driven out of the lettuce and cauliflower waste, but it should produce at least 1.5 cubic metres of good compost.
The finished compost heap
Finally I make a note of the date and give the heap a code on the whiteboard in the workshop, where I will record the temperature of the heap from time to time. What I want to see is that it gets into the 50-65 degC range for at least a few days, and that it doesn’t go into the 75+ degC region for more than a short period, otherwise I’ll have to turn the heap at that stage to drop the temperature. Then, once it has done about a week in the 50-65 range I’ll turn it when it’s convenient. After that, once it drops to around 40 degC (not lower) I’ll turn in every few days to a week, making adjustments to water content and the time between turnings to try to keep it above 40 for two or three weeks. After that I’ll make sure the last turning has moved it to a place where it won’t be in the way of the next batch or other work, and just keep an eye on it’s progress and of course, the smell.
By the way, do you see the fork in the last photo? That’s a manure fork, with four tines rather than the three in a pitch (hay) fork. The tines in the manure fork are closer together, and they are fatter as well as having a bend (or a significant curve) so it’s easier to push them under things on the ground. Pitchforks are all very well for throwing sheaves of hay onto haystacks, but I find that they don’t pick up the shorter, looser material like compost ingredients or manure very well. And they’ve (finally) started to become available in Southeast Queensland – at Mitre10 and Trade Tools if you’re looking for one.
* More thoughts on waste in the vegetable production system:
It’s difficult to get a good idea of the level of real wastage in the fruit and vegetable production system. A Bush Telegraph episode on ABC Radio National on 14 July gave a figure of “$10 billion worth of food” wasted annually by “Australians”, but this isn’t broken down beyond “food”. Later in the same article they quote figures of “between 20 and 40 per cent of fruit and vegetables grown” being rejected before they reach the shops “because they don’t meet supermarkets’ high cosmetic standards and specifications”. However I suspect that there are different rates for fruit and vegetables going to landfill. For example, any fruit with large seeds (avocados) would be unsuitable for stock food, for instance, as are whole potatoes, because of the risk of choking. Apart from what is diverted to stock food at the farm or packing shed, some of the “unsuitable” fruit and veg goes to charities for distribution to low income families.
What I’m not sure about is whether fruit and vegetables grown under contract to the big supermarkets is prohibited from being sold as a condition of contract. I’ve heard this said, but haven’t been able to find any evidence one way or the other. It would be interesting to know.
It would also be very interesting to see a detailed breakdown of the different destinations for rejected fruit and veges.