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1. When composting, start with an airy bed of carbon as the first layer of your compost bin or pile. This allows oxygen to move through the bin, and also acts as a sponge to suck up any excess moisture. This base layer needs to be made from a combination of soft and woody carbon to allow constant airflow. If you simply use ripped up paper, it will break down too quicky. Add some structure by using wood chips, twigs, or bark mixed with carbon rich, softer sources like cardboard or fallen brown leaves.
I always start my compost bins with a fluffy layer of wood chips that I harvest my compost off, so they get used numerous times before they break down. Fungi love wood chips too, so it’s a win/win!
2. Putting in heaps of brown matter (brown leaves, paper towels, ripped cardboard, etc.), with every bucket of greens (food waste) is a MUST for composting. Remember ‘brown is best then chuck the rest’. You need to add in at least double the amount of carbon to nitrogen, ideally more, as the ideal C:N ratio is based on weight rather than volume. Adding carbon is important because it provides compost micro-organisms with energy, much of which is released as carbon dioxide and heat, and the nitrogen in your food scraps and green garden waste provides nutrition to microbes for growth and reproduction.
3. Composting occurs most efficiently when you have bigger volume. If you have the space, I love working with 400L bins because you can even try out hot composting.
Keeping your bin well topped up may involve scrounging for other people’s waste. ShareWaste is an awesome app for connecting you to neighbours who have scraps to give away. Local cafes produce a lot of waste too and are receptive to giving it away, as it helps to keep their overheads down.
Coffee grounds are compost gold and help to heat up your compost because they’re high in nitrogen and have a relatively neutral pH. Make sure you communicate with the cafe clearly and work out a system that is simple for you both.
4. Just like us, your compost needs to breathe. Aeration is super important if you want finished compost fast, as oxygen fuels the fire of you compost. You can use a compost aerator (looks like a giant corkscrew) or a garden fork to turn your compost.
If you aren’t able to do this (it can get heavy), here are some alternative aerating hacks; wiggle a star picket (metal garden stake) through the mass of compost, all the way down to the bottom of the bin to allow air to flow.
Or get your hands on a PVC pipe cut to the internal height of your compost bin and drill numerous holes all over it. Position the pipe in the centre of your bin and it will act like a lung and draw oxygen into your pile.
5. Compost works best with 40-60% hydration. The best way to test the moisture content of your compost is to grab a handful and give it a squeeze. You only want a couple of drops to come out. It should feel like a wrung out sponge.
Depending on the weather you may need to add extra water, but be careful not to over-wet the contents of your bin, as the compost will become anaerobic, start to stink and the decomposition will slow down.
Dry carbon is an important addition to balance out your food waste, if things become a little slimy. On the other hand, a dry bin will just sit there doing nothing. It does take trial and error to work out the correct moisture levels.
6. Welcome composting mates like worms, black soldier fly larvae, mites, slaters, isopods, and beetles into your compost. These are good guys in your heap and its great seeing a diverse mix.
A well-managed compost system will promote good bug action to help with efficient processing of your waste. Adding soft carbon (ripped cardboard, egg cartons, brown leaves, etc.) creates habitat areas for bugs to hang out. (Who wants to sleep where you eat?) The vigorous appetites of hungry insects help to aerate your compost; just like worms, bugs tunnel as they eat, leaving behind air pockets. So don’t freak out if you see other creepy crawlies in your bin, aside from well-loved wormies, as a mixed-bag of bugs will boost the population of bacteria and fungi in compost through their excretions (fancy word for poo!) which then speeds up the composting process.
7. We all want to make compost that’s the best it can be, and compost activators give your heap a glow up. A compost activator’s job is to provide an injection of nutrients and high levels of nitrogen to the microbes allowing them to multiply and fire up your bin.
Activators come in a number of different forms including: Bokashi compost which is jam-packed with good bacteria that will inoculate the organic matter in your compost, helping it all to break down far more quickly. Plants with high levels of key minerals (comfrey leaves are king, but dandelion, yarrow leaves, stinging nettles, tansy leaves are great too). Manure from cows, sheep, rabbits and chickens, etc., for urban gardeners, pelletised chicken manure, Dynamic Lifter or Blood ‘n’ Bone are useful additions when added sparingly.
Finished compost or a handful of healthy garden soil, which is loaded with good bugs and bacteria, can be added back into your new organic matter in your compost system to get the party started. Other wacky yet effective activators (if you’re brave) include: Burying road kill in the centre of your compost, adding urine (stinky but powerful) and using fish scraps.
8. You need to think of compost conditioners and activators as the ‘cherry on the top of your compost cake’, rather than a major input. So don’t over do it! Many people assume manure, especially chicken manure is acidic and that is simply not the case. It actually is quite alkaline, as is crusher dust, wood fire ash and garden lime.
Compost microbes operate best under neutral to acidic conditions. During the initial stages of decomposition, organic acids are formed. The acidic conditions are favourable for growth of fungi and breakdown of lignin and cellulose.
As composting proceeds, the organic acids become neutralised, and mature compost generally has a pH between 6 and 8. If you add in too many compost conditioners, you’ll throw this pH out of whack and end up with really alkaline compost that many plants will not thrive in.
It’s interesting to note that a lot of cheaply made commercial compost tends to be alkaline, as they pile in poo!
9. Don’t forget to cure your compost. Heat can become such a focus of quick composting that gardeners forget that several important degradation processes go on only at cooler temperatures.
As the heat-loving thermophilic bacteria die off, mesophilic bacteria that thrive at temperatures between 21-38ᴼC (70-100ᴼF) re-establish themselves and continue the composting process. Fungi and actinomycetes also flourish at cooler temperatures. Both play important roles in breaking down tough lignin in the remaining woody material. To allow beneficial fungi to infiltrate the curing compost, make sure the pile is in direct contact with the soil on the ground.
Most of the larger organisms, such as micro-arthropods, beetles and the precious composting worm, can’t withstand the temperatures in a hot pile, as the temperature of your compost moderates, they move back in. this ensures that when the compost is spread it will contain the full range of organisms that make compost so vital and valuable. If compost is not left to cure, these micro-organisms do not have time to repopulate the pile.