Wood pellets for substrate - anyone use them?

[Bonsai Nut]

I have recently been going on a deep dive with wood pellets as a soil component. They can be purchased in bulk as farm stock bedding (usually pine pellets) or as fuel pellets for wood stoves (usually hardwood pellets). These pellets are typically compressed sawdust that otherwise perform similarly to a core of the corresponding wood type. No additives (binders, fungicides, etc). No toxic chemicals (since they are designed for animal bedding or burning).

When they are moistened, they almost immediately break down into sawdust of the corresponding wood type. So at some level I'm wondering what the pros/cons are of using hardwood sawdust in your soil mix alongside pumice or other inorganic materials. I immediately worry about water retention... but then wonder how much different it would be from using pine bark fines(?)

FWIW mushroom growers use this as a stand-alone soil to grow food mushrooms. There are numerous YouTube videos out there. Mushrooms grow on damp (but not saturated) substrate - similar to rotting logs.



What happens when you water wood pellets:

 

[Gabler]

I'd be concerned about allelopathic chemicals in the sawdust if the sawmill was cutting black walnut or something.

 

[Flowerhouse]

In my distant past, I used sawdust from a sawmill as a soil amendment. I was using it to loosen up the clay in my central Kansas garden. The county extension office advised that sawdust uses a lot of nitrogen in the process of decomposition, so less nitrogen was available to plants. That's what I'd worry about in using sawdust for bonsai.

 

[Maiden69]

IDK, with coco coir available, why use saw dust? I use those pellets for my Traeger smoker, when they get damp they turn to mush. I guess you can call it sawdust, but it stays clumped up. At least you can shred coco coir and have it evenly spread on the soil.

There is a brand that sells actual wood charcoal pellets, and they state that they are damp (not sure if wet) resistant. Royal Oak, might look at that before looking at wood pellets. But again, might as well get biochar.

 

[Michael P]

Interesting. Do you soak them before mixing with inorganic components? The warning about nitrogen deficiency is valid, but in bonsai mix the proportion of saw dust would be low . And we can fertilize to compensate.

 

[stubmle]

If I recall right, our own @Leo in N E Illinois has mentioned using hardwood sawdust as a soil component for blueberry & other ericaceous plants. Something about myccorhizal development, I think.

 

[WNC Bonsai]

I would think it would clog your soil similar to using peat humus, as well as competing with your trees for nitrogen. I use composted tree bark (Lowes Natures Helper), and sift out the fines same as with my other soil components. Composting uses up some of the most labile organic matter and reduces the nitrogen demand.

 

[Wires_Guy_wires]

I have used them over a decade ago and I never used them again.
The particles are super small, comparable to sawdust you get from sanding. As opposed to sawdust from sawing, which tends to have more body.
The way they're pressed also tends to break rhe fiber structure so microbial life doesn't like living in it.

If you want to use it, 2-5% of your soil should be no issue. Anything above that, would be problematic.