“Increasing the humus content of agricultural soil has always been a principle objective of organic agriculture. Changing the management of farmland to use organic or permaculture strategies and techniques can rebuild this storage of carbon, fertility and water to close to those of natural grasslands and forests. It is arguably the greatest single contribution we could make to ensure the future survival of humanity.” – David Holmgren, Permaculture – Principles and Pathways Beyond Sustainability
The composting method that we use at the Panya Project and that is often used in Permaculture Projects is the 18-day quick composting method afterBerkley. We need a mixture of carbon and nitrogen elements in a ratio of 30 to 1. This is however in concentration, not in biomass, where it’s probably more around 3 to 1, fully depending on your chosen and available ingredients. Water is added to the mixture with a moisture content of 60 percent being optimal. It is an aerobic fermentation process generated through heat. The pile is stacked in lasagne-style, meaning layer for layer altering between carbons – low nitrogen – carbons – high nitrogen – carbons – low nitrogen – and so on.
Carbon is the building block of life and is mostly found in trees. For the compost you can chose most brown organic material like branches and old leaves. For the quick compost it is important that most material is quite small; huge pieces of wood won’t compost in a month or 18 days. The highest nitrogen source is probably pee, then different kinds of manure. Another source of high nitrogen is freshly cut legumes as they are plants that catch nitrogen from the air. A middle and low nitrogen source is all other freshly cut leaves and greens from the garden and the trees. Kitchen waste is, depending on what it contains, mostly on the more or less right carbon-nitrogen ratio of 30 to 1 and can be added in between the layers.
The layers shouldn’t be higher than10 centimetreseach, keeping layers of cow manure thinner. The pile is optimally between 1.5 and2 metrecube, should never be smaller than1 metrecube, as it won’t get hot enough. After 2 to 4 days the pile mostly reaches a temperature of about 60 degrees Celsius. If the pile is after four days still below 45 degrees, you might not have the right moisture or there isn’t enough nitrogen in the lasagne. If the pile gets too hot, meaning more than 65 degrees and often predominantly covered in some white bacteria, it’s defiantly time to turn it. If it keeps heating up like that you might have to put some more carbon material. The pile should be covered to keep it from drying out in hot climates and keep it from getting too wet in wet climates.
After the first four days, the compost should be turned every other day. This keeps it aerated and gives you the possibility to add some materials, mostly water if necessary. You can check the moisture content in pressing the material in between your hands. If the hands become slightly wet, with not more than one drop of water on your palm, it is perfect moisture. The temperature you can feel with your hands, if digging into the pile and it’s too hot to keep your hands in it must be about 60 degrees. You have to dig in because the outside 10 to20 centimetresdon’t heat up and don’t really compost. Therefore, if you want the composting process to finish in optimal time it is important to turn it right; that means that you bring the outside of pile to the inside and the inside to the outside with every turning.
In the Panya Project, we usually have a pile done in about a month. Through this composting method we can keep planting all year through in the same beds always adding fresh healthy soil to the plants.
In permaculture we look for the multiplication of our functions. Doing this with the compost, we see that one output of the compost that we could use is the heat; probably we could cook eggs on top of it. When we had 20 school kids from Bangkok visiting the Panya Project for a week we thought we need more hot water options than our solar collector who holds water for about 4 to 8 showers. So we built them a bucket shower with passiv heating in letting the pipe run through the 60 degree hot compost. See pictures below. For two weeks we managed to have hot water from that pipe, so hot you needed to mix it with cold water.