By Stephanie Brash, Master Gardener, SCMG
Have you ever wanted to try your hand at composting, but were afraid it would be too difficult? Too labour intensive? Smelly? Well, it’s time you gave “hot composting” a try! It can produce wonderful, rich compost in only a few short weeks, and will be virtually weed-free!
The term “hot composting” refers to a process in which microbial activity is at its optimum level within the compost pile, which results in finished compost in a fraction of the time of cold composting. Hot composting has the added benefit of killing weed seeds and diseases due to the heat it generates within the pile. It requires a bit of effort, time and diligence, but if you’re in a hurry for it, it’s well worth a try.
When putting together a nice pile for hot composting, try to make layers of “brown” bulky materials (leaves, dead plants, old mulches) with high energy “green” stuff like fruit and vegetable scraps. Clean out your fridge and grab anything that has started to rot. Clear the freezer of things you’ll never eat. With hot composting, you mix the materials instead of layering them, and you try to work with smaller pieces to accelerate the process. Aim to have around 1/3 “greens” (nitrogen-rich) with 2/3 “browns” (carbon-rich). Lastly, water your pile so the ingredients are evenly moist.
Don’t stress about getting a perfect mix the day you build your pile! Hot compost is forked and turned again and again. Instead, aim for building a decent sized heap that is around 4 feet by 4 feet. A metal rod inserted into the middle of a hot composting pile can serve two purposes: it can be a heat gauge you can feel with your hands, plus you can jiggle it around to aerate the pile.
Once a hot heap is built, don’t touch it for four days. This lets the moisture equalize while your bacteria is getting established. After four days, chop through the pile with a hoe, and you should be rewarded with pockets of heat. Fork the material back into a pile, and cover it with a tarp to keep the rain away.
Keep your heap protected and turn it every two to three days for two weeks. Obvious heat and maybe even steam will be evident through the first couple of turnings. If you have a soil/compost thermometer, your compost pile should read between 55-65˚C. However, you can also stick your hand into the pile; if it feels uncomfortably hot, the temperature is perfect.
Now, the temperature will drop in your pile after a week or so. This is normal. Continue to turn and aerate the mix every couple of days for another week or so. Although active decomposition is almost complete by this point, the compost will continue to improve if you give it time to cure. Allowing your compost to mellow for a month or so allows the microbes to settle down, and the texture of the mixture relaxes, becoming dark and crumbly. You can cure your compost in buckets sheltered from the rain, or simply cover the pile for a few weeks.
Hot composting takes a bit of effort, attention, and diligence, but your gardens will thank you for it!