Sunday, October 11, 2015

Making rotten wood!

Remember when I said I had stuff "brewing" in the bug room? Well I really should have said fermenting, because that is exactly what I'm doing, fermenting Traeger wood pellets to make rotten wood! All it takes is Traeger wood pellets, flour, and yeast! (I think active dry yeast is the best).

First you take a bunch of wood pellets, and then pour hot water on them, and then they expand, kinda like the coconut fiber bricks. So remember, a cup of pellets makes lots of sawdust, so don't use too much! Then you dry the sawdust out, add flour and yeast, stir well, and then add some water to make it moist again. Put it in a well ventilated container, stir it daily for about a month, and bam! You have rotten wood! (Fermenting times can vary though, keep that in mind!).

While fermenting, the temperature of the wood rises, and it feels hot to the touch. When it is done fermenting, it will return to normal temperature. If used while still fermenting, you will probably bake your bugs alive, so you gotta wait until it is done fermenting. Here are my ratios for the wood and flour and yeast:

Roughly 10 cups of sawdust (not the actual pellets, the resulting sawdust!)

1 cup of flour (I used bread flour, I'm pretty sure you can use any wheat flour)

And one small packet of active dry yeast (I think I should have used a little more yeast, but whatever, it's my first try!)

Here are some pictures of the wood! (So interesting, right?)

In case you didn't know, rotten wood is needed as food for many different invertebrates, rhino beetle and stag beetle larva for example. Lots of click beetle larva like to eat it too, so it is a good material to have on hand. Today I noticed the wood was getting hot, so the fermenting process has begun! Will keep you guys posted on any interesting developments! Hope you guys enjoyed! :)

EDIT 1/12/2023:

This recipe worked for me this one time, however I'd like to note that two subsequent attempts I made to replicate this batch both ended in failure. I believe it was because with my subsequent attempts, I used normal all purpose flour, rather than bread flour like I did this first time. This is by no means a professional flake soil recipe, but this first batch did in fact ferment properly and made useable flake soil, as you can see in my subsequent posts here.


  1. Wish I'd seen this when I had rhino beetle grubs !

  2. Yep, it's a pretty nice method for when you live in an area without forests (Like where I live, its all scrubland here).

  3. Just so future readers know, I'm pretty sure I used Hickory pellets for this batch, and it worked just fine for the inverts I fed it to, and no longer smelled of hickory by the end of the fermenting process. I unfortunately made the mistake of storing the finished product in its humid state, which in turn led to a lot of it being consumed by fungus gnats before I could really use it... So don't do that, if you have excess, let it dry out well before storing it.

    Additionally, I tried tripling the recipe myself a couple years later with Oak Traeger pellets, and it did not work for some reason. Even with the same overall proportions, the mixture just would not heat up fully or stay hot for long, smelled awful, and didn't have much mold growth at ALL. The latter leads me to believe it was contaminated with some sort of anti-fungal chemicals or something, which likely screwed the whole process up.

  4. Also, for your convenience, I've given all posts pertaining to this particular project the tag "DIY flake soil", which should make finding the other posts in this series much easier, simply look to the Labels section on the right sight of the blog.

  5. Would this be good to use as millipede substrate, and for growing mushrooms in? How do you know if your rotten wood has fermented correctly? I hear this can kill your beetles if it is slightly off. Would love to know more details about this process! What temperature do you keep it at to ferment? Can you dry this wood once done fermenting for long term storage?

    1. Sorry for the late reply!

      This would be great for millipedes, but perhaps not for growing mushrooms in, as it'll have been colonized with several other molds/fungi, (which is what aids in the decomposition process), and I hear that you generally want quite a sterile environment when growing mushrooms, as they can easily be outcompeted or consumed by other molds/fungi.
      If the wood is properly decayed, it'll have an earthy smell, and won't heat up after being stirred. The latter is quite important, as if it starts heating up (fermenting) again while beetles are in the substrate, it'll kill them.
      I believe 75F°+ would be best for fermenting, the warmer the better. And yes, you should dry it out when storing it, lest fungus gnats get in and turn it all to frass...