Flake soil is an all-purpose food and substrate commonly used for raising beetles in captivity; valued for its ease and speed of production. All our captive-born-and-bred beetles use this as their food source during larval stages.
For beetles that feed on rotten hardwood as larvae, flake soil functions as artificially rotted wood. Making flake soil uses yeast to ferment an additional food source and produce a beneficial environment for molds and bacteria to colonize wood in order to break down the hard lignin content. This allows the larvae to more easily digest and extract the cellulose content. The additional food source also provides extra protein and nutrition for the larvae, helping to insure a large, healthy, and long-lived adult form.
If you’d like to opt for making your own flake soil to raise beetles (flake soil also makes an excellent additive in substrates for other detritivores, such as isopods), below is the the same recipe and process we use to produce one full batch of our own flake soil:
- 40 lbs. of oak barbeque pellets
- 15 lbs. of whole wheat flour
- 6 gallons warm water (tap should be fine)
- 2 packets active dry yeast
- 4 66 qt. lidded bins or 5 gallon buckets
These are just the quantities we use for one “batch” of flake soil at a time, and can be scaled up or down to meet your needs or space limitations!
- Divide the oak pellets into equal amounts between the four containers (10 lbs. each)
- Add an equal amount of the warm water to each container and mix in order to rehydrate the compressed wood pellets back into sawdust. The wet sawdust should be able to clump together when squeezed without dripping water. Letting the pellets sit for 15-30 min after adding water helps determine if more water is needed. (~1.5 gallons each, though you may need to add up to another quart to each in order to thoroughly rehydrate all the pellets)
- Divide the flour into equal amounts between the containers and mix completely so that no pockets of flour or clumps remain. Make sure to scrape all corners and sides along the bottom, as uneven mixing can lead to issues with the ferment later. (3.75 lbs. each)
- Sprinkle half a packet of the active dry yeast into each container and mix again to distribute.
- Lid each container and place in a location with a relatively constant temperature, room temperature or a bit warmer preferably. Due to the smell of the fermentation and formation of mold, keeping the containers somewhere more isolated is recommended such as a basement, workshop, or garage. Cooler temperatures can work, but the fermentation may be slow and require additional time to reach an optimal breakdown of wood. Poke holes into the flake soil to increase airflow to deeper areas.
- For the next 2-3 weeks, each day open and mix each container well. Turn over and aerate the flake soil, again making sure that corners and bottom edges are scraped to ensure no pockets of undesirable decay form. The flake soil will begin to smell bready or winey as the yeast ferments the flour and the interior of the bins will begin to warm up. Make sure that any condensation that has formed on the lids is added back so that the flake soil does not dry out while fermentation is ongoing. During this time, mold will typically appear to begin colonizing the sawdust, this is okay. Mixing daily during this time is also important for preventing mold from turning the loose flake soil into large clumps that need to be broken apart.
- After three weeks, mixing can be done every other day or so until the flake soil has reached an optimal level of breakdown. Typically this is about two months at room temperature, though it can take up to four depending on your conditions. The color of the flake soil will be a dark brown, and the scent will be earthy like fresh dirt. At this point it is ready for use, or it can be dried out to stop the further breakdown for longer storage.
The consistent mixing schedule is key for an optimal end product. The better the flake soil is mixed initially and daily, the fewer hard clumps or balls of substrate will remain in the finished product. Clumps are not harmful, but may be unevenly broken down compared to the rest of the flake soil.
If your flake soil begins to take on a rotten or fecal smell, or you can see patches of lighter yellow/tan forming, it may be too wet. Those areas are not getting enough oxygen and are beginning to decay from going anaerobic. Leave the containers open for a few days to let some moisture evaporate and keep mixing daily.
If there is no condensation on the lids or the fermentation has not started after two weeks, check if the flake soil is too dry, and add water and optionally more yeast.