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Mark Warner

My Composting Golden Rules

Composting can be a tricky business! There are numerous ways to do it and confusingly they are all right, just to a greater or lesser degree for you personally. It gets very specific in terms of location, ingredients and handling and at the end of the day you need to experiment and monitor closely to find out what works best for you. This is an investment of time, energy and patience.

The Ridan In-vessel compost machines

I use highly insulated in-vessel-compost machines as I need to get large volumes of food waste to break down quickly. The machines will break down food waste, woodchip and coffee grounds to an unrecognisable state in one week with a further three weeks at temps of over 50 Degrees Celsius in maturation boxes before it can be made into a sale-able product that will improve your soil and give valuable nutrients to your plants. However, I think there are some golden rules that apply to most, if not all, composting:

 

Rule 1 - It's all about the ratios!

Start with 50% brown material and 50% green material, then increase or decrease based on results. Brown, includes cardboard, woodchip, newspapers, sawdust (not too much) and dead leaves. Green includes fruit and veg waste, grass clippings and even weeds. This is to get the balance right between Nitrogen (provided by the green waste) and Carbon (provided by the brown waste).

 

Rule 2 - Hot is good

This is a bit contentious as more traditional composters are happy for it to take a longer time with temperatures reaching approximately 30 degrees C. But like everything there is a balance to be had. If kitchen waste is not composted quickly it can start to smell, attract rodents and flies and produce an anaerobic environment. To get warmer temperatures simply apply the Fire Triangle - Fuel, Oxygen and Heat.

Fresh woodchip is a good source of fuel as bacteria from food and the general environment eat the cellulose, a by-product of this is heat. Aerobic bacteria need oxygen so turn your heap to get that oxygen back in.

Note: Fresh woodchip only. If it's partly decomposed it wont generate the temperatures.

In this picture you can see I cover my heap (the 4th and last stage of maturation) with a semi-permeable membrane. The snow has melted because the core temperature was 57 degrees C.

Note: mass is also important. Small amounts of green and brown waste wont generate heat. You need a reasonable quantity to get started, about a cubic meters worth of green and brown. Temperatures also take a while to build so don't rush it.

 

Rule 3 - Let it breath

How much air you get into a compost heap depends on how energetic you are and how much time you have. It's hard work. Tumblers are great because they are easy to turn but they must be turned regularly. I turn my in-vessel compost machines every two days when I add fresh food waste and woodchip. This allows the heat to peak in the existing mass and bacteria to multiply before disrupting everything with fresh cold waste.

In the picture above I have three maturation boxes. I turn from one to the other every week before it ends up in the heap.

 

Rule 4 - No liquids

To start with. This includes gravy and custard. By their nature liquids take away heat and cause an anaerobic environment. When you turn your compost you will be able to judge if it is too dry. At this point, and only if it's dry, use a watering can with a fine rose (sprinkler head) on it to moisten the pile. Do this by turning a 6 inch layer and watering slightly. Turn another 6 inch layer and water again - repeat until the pile is fully turned.

 

Rule 5 - No pets please

Hedgehogs and other cute mammals like warm compost heaps, but to avoid nasty accidents with spades and folks they are best kept out! A pallet construction with wire mesh around it will keep mammals out but allow air and worms in. You might want to dig these into the ground a few inches to try and stop them burrowing underneath and into the heap. For dalek type bins simply attached wire mesh to the base of the bin.

This is the first maturation box I made back in 2016. It's made out of a large thick plastic pipe used to store grain, wrapped in 5mm sheets of insulation, a plastic protective sheet and wire mesh for good measure.

Overkill, perhaps, but I still use it today and it gets great temperatures. The door at the bottom was a waste of time and I've replaced the paddling pool with a proper lid.

God knows what the neighbors thought!


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