If you can fill a brown bin you can fill a compost heap, says Fiann Ó Nualláin
who outlines why this practice is essential to sustainability when it comes to our gardens as well as the planet
I have been lifting a lot of produce this week and refreshing the beds with some compost ahead of the next rotation of sowing and planting out. I’ve also been starting a new compost heap as I try to be mostly “no dig”, and top dressing is vital to get those worms in and up to aerating soil and making the top layer of my soil, root expansion ready. Any time I get to this point in the garden I always think of the old Cherokee parable of the two wolves.
That’s just how my brain works but it’s a good one for life in general and for the garden overall.
You may have heard it a million times but basically a grandfather is talking to his grandson about life and human nature. He tells the boy that there are two wolves inside each of us: A good one that holds our bravery, our kindness, our love and compassion and also a bad one that carries greed, hate and fear.
That every day they do battle to see which energy will eventually win out. The young boy asks “Grandfather, which one will win in me?”. The grandfather replies, “The one you feed.”
So whatever about feeding our good wolf, feeding the garden is a right thing to do. And in the urgent need to be sustainable like our life and planet actually depends on it, a compost heap is a must. The thing is that composting can commence any time. You could start a heap today; you could start one in the middle of winter. Kitchen and garden waste wants to decompose, why not let it be into compost rather than landfill? If you can fill a brown bin you can fill a compost heap.
Today’s heap might break down kitchen scraps and garden waste faster and deliver good friable compost quicker but once the conditions are met, a heap will yield or at least work towards it, at any time of year. So if you haven’t one, no excuses, and if you have here’s how to keep it fully active.
It has hardly been the driest August so unless you have a covered compost heap, it will have been soaked through a few times lately. That’s a good thing. One of the mistakes commonly made with heaps is to pile everything on but never add in any moisture. If you have a covered heap then remember to give it a sprinkle every now and then as moisture is essential to microbial activity.
Composting needs moisture and heat to fuel its decomposition, to maintain a good environment for decomposing bacteria to thrive. Composting is most efficient at a moisture content of around 40%-60% by weight. That seems a lot but it’s not a puddle at the bottom of it, it is well distributed throughout, it is what coats the humus molecules of the forming compost.
On the other hand, a soggy heap is just a heap of stink. Too much water will fill up air pockets and turn the heap anaerobic and make it distinctively foul-smelling. Sogginess is rot and stagnation rather than organic breakdown and steady activity. So if there is a pong then the thing that’s wrong is excess water. It might need a turning to loosen up and initiate drainage or it may also need a cover to limit rain access.
Often it is the extra moisture content in grass clippings that is the smelly tipping point, especially if that is the bulk content of the heap — as can be the way all summer. This is why it is best to think of the heap like a lasagne and layer it out with greens, browns, wets and dry. It is not an exact science but the aim is toward a balance for sustained microbial activity.
Really what makes the heap — what does all the work — is the microorganisms that adequate moisture also sustains. A single teaspoon of end-product compost can contain as much as a billion bacteria so the process provides you with powerful microbes that bolster the health of your garden soil.
A heap is all about the bacteria. The bacteria to break it down and the good bacteria that ends up in your soil. Getting that initial bacteria right is the answer. And getting that right is to a large degree how much rain you let in lately. In essence, there are two types of bacteria that colonise heap:. Aerobic (requiring oxygen) and anaerobic (surviving without oxygen). Aerobic bacteria thrive in non-soggy well-aerated heaps, anaerobic in sodden or compacted ones.
The anaerobic ones are 80-90% slower in breaking down material than the oxygen-fuelled types. Those are the heaps that take years not months to transform into a workable crumbly compost. The anaerobic type also secretes amines — ammonia-like substances and also hydrogen sulphide.
Because anaerobic bacteria thrive in a soggy heap, letting the heap dry out will reduce their number and help the aerobic ones mount a comeback. It’s a bit like gut flora, there is bad and good and one can outdo the other and like that old tale of the two wolves — feed the good one. So if your heap is compacted or hasn’t been turned yet then it needs to be fed a little air — turn it this weekend and that will invigorate it.
It will do its thing faster. So, if the heap is dry, water it, if it is soggy you know what to do. You can howl at the moon on your own time.