Howdy! Welcome to the second segment in out series on the Life of a Batch. In this segment, we’ll talk briefly about how we monitor a batch of compost during it’s life at the Factory.
Previously:
We built a new batch, from raw materials, to layering, to watering, to finish.
We setup the batch on Monday, February 2, and now it’s Friday, February 6 – four days later – and as you can see, the batch has already shrunken significantly. I’d say, it’s down almost a foot from where it was when we set it up. This is very common, as the material settles and the microbiology starts to go to work. You’ll notice, over the first month of composting, the batch will lose about half of its volume. This is why we setup two bays to start.
The three main things we monitor over the course of a compost batch’s breakdown are temperature, moisture and smell, with temperature being the best indicator of the activity level throughout the life of the batch. It’s something we check several days per week.
The initial phase of the type of composting we do – Active Hot Composting – is called the Thermophilic Phase. This is when the pile microbiology is dominated by heat generating bacteria. As these little guys go to work, they heat the place up. Ideally, we want to keep the temperature between 131°F and 160°F (55°C – 71°C). Keeping the batches in this temperature range for several days kills weed seeds, pathogens, and keeps the decomposition process moving along quickly.
As you can see from the photos above, at the four-day mark, the left bay is at about 150°F (66°C) and the right bay is at about 158°F (70°C). So, our microbes are clearly getting busy. We’ll keep an eye on the temperatures as we go, but this is a great start.
As for moisture levels and smell, we’ll get a better sense of those when we get into the pile to turn it, which should be around the middle of next week, weather permitting.
Next up:
The first turn. This is where the material gets mixed for the first time, and things can really start to heat up.