Creating Hot Compost – A Temperature Guide
A hot topic today is waste, food waste specifically. Did you know that approximately one third of the food produced in the world for human consumption every year — roughly 1.3 billion tonnes — gets lost or wasted. Fruits and vegetables, plus roots and tubers have the highest wastage rates of any food. All of which can very easily be composted, a fantastic and natural way to get rid of excess food waste. Once the composter is doing it’s job you an even spread the finished result onto your flowerbeds, improving soil quality and reducing the need to use chemical fertilisers and pesticides.
There are two different methods of composting: Vermicomposting and Hot Composting. Both methods are very effective and great for the environment however today we will be discussing Hot Composting.
Hot Composting involves throwing organic waste into a large bin or pile. The material then starts to break down using an aerobic process. This method can only really be done outdoors and can handle any amount of organic material. A hot compost pile can easily reach temperatures of 49°C – 77°C in a matter of days, this can produce compost in around 4 weeks if done correctly. You could even use the high temperatures to heat your water, home or greenhouse. Monitoring the temperature of the hot compost pile is a very key step because remaining at a temperature of 65°C or higher for more than a few hours will kill off beneficial microorganisms that add to your compost.
What You Need:
Equal parts green and brown materials. Fresh grass clippings are great for your first try because they’re already in small pieces, and are full of moisture.
A compost thermometer ( we recommend the ETI Compost Thermometer, a bi-metal dial compost thermometer incorporating a colour-coded, easy to read dial)
A fork or shovel for turning
A tarp (optional)
A bin/container (optional)
- Ensure that all the organic matter you are using is chopped into small pieces and combine with brown and green materials as well, You should also add in around a shovelful of pre-made compost or soil, this will be full of microorganisms which will help to jumpstart the process.
- As the pile starts to build, sprinkle it with some water to keep the organic matter moist.
- The pile should be roughly one cubic metre in size. Too much larger and the moisture and heat levels will be wrong for a speedy and efficient decomposition. At this stage you could cover the pile with a breathable tarp to maintain moisture, but this isn’t necessary.
- Over the course of the next month or so you will need to monitor the temperature of your Hot Compost pile daily with your Compost Thermometer. In the first five days the temperature of the pile should rise, between 49°C and 77 °C. The temperature will depend on moisture levels, the size of your organic matter and the size of your pile.
- Once the temperature begins to cool to below 43°C (usually around 5-7 days) you will then need to turn over the organic matter to introduce oxygen, this will then heat the pile up again.
- When turning the pile ensure that you push the exterior material into the interior, enabling everything to be broken down evenly.
- You will need to continue to monitor and record the temperature of the pile everyday and turn the pile every 4-5 days, you can moisten the pile with some water if needed. After roughly one month you should have turned the pile four times.
- At this point most of the Hot Compost pile will be a dark, crumbly compost and the temperature should have decreased below 29°C.
- Now you need to let the compost ‘cure’ for a few weeks before using it. Perfect for using on your flowerbeds.