Process bark chunks into smaller bonsai substrate

[Cruiser]

27 gallons of small nugget df bark. $10.00 from a local landscape supply.

The chunks are mostly too big to use for bonsai. Sifting nets some useable particles, but not many; and definitely not worth the time and labor involved.


Bark chunks need to be broken up. What is an efficient way to do this?

An electric chipper. (My wife bought this one used for $30.00.) Most are too weak to handle serious tree work, but they can gobble up small branches nicely.



I decided to chip and process 10 gallons of bark.
Chipping took 13 minutes. Here is what the bark looked like after. Most pieces were reduced to 1/2” or under.



Chipped bark was then sifted through a 1/2” screen.

It took 10 minutes. Sifted particles are 1/2”+. Most wood shards were removed at this step.

Remaining…



Remaining bark sifted through a 1/4” screen.

This step took 12 minutes. Sifted bark ranges from 1/4”- 1/2”.

Remaining…



Remaining bark sifted through 1/8” screen.

This time it only took 8 minutes. Sifted bark is 1/8”-1/4”. It looks just like fine-grade orchid bark.

Remaining fines…


Particle size comparison.


RESULTS:

Particle size distribution of chipped small nugget df bark:

<1/8”- 9%

1/8”-1/4”- 26%

1/4”-1/2”- 37%

>1/2”- 28%



Time involved to process 10 gallons

43 minutes total

Chipping- 13 min

1/2” sift- 10 min

1/4” sift- 12 min

1/8” sift- 8 min



Was it worth the effort?

For me, yes. I utilize 1/8” up to 1/2” particle sizes. For 6.3 gallons of sifted product it cost 30-40 minutes of time and about $3.00.

For comparison, 2 gallons of 1/4” df bark ordered from online costs $34.00 plus shipping.

Also, from a non-monetary standpoint I prefer to use df bark as a bonsai substrate. It’s a by-product of the timber industry, is locally sourced, and roots appear to love it.

 

[nuttiest]

Sometimes depot has that pine mulch, it is super-shred and great potting soil. I use the mini nuggets now and with a little peat, perlite and lime it is fine for 3 gallon or larger pots.
I like your screens. Ever think about building a giant upright column of successively smaller screens and dumping in the top? It would need wheels so it could be shaken back and forth

 

[Cruiser]

I tried the column approach using 3 nested 5 gallon buckets. No wheels below.

Bucket bottoms were removed then screen was attached. 1/2”, 1/4”, and window screen.

It didn’t work as well as hoped. It was annoying to shake and pry apart the buckets to remove substrate.
Perhaps if there was more surface area to process more material at once and if there were wheels it might work better.

 

[nuttiest]

Old filing cabinet or dresser, but then you would have to cut through.

 

[Cruiser]

I should add…
My biggest takeaway from this is that a shitty electric chipper works great for breaking down large bark chunks into ideal sizes for bonsai.

In addition to the small nuggets, it also chips pieces up to 4”.
Larger chunks may even be preferable to the small stuff since there seems to be less wood mixed in.

 

[nuttiest]

That is the perfect size ... I like to put large grain pool filter sand with that size because because the pieces still touch but are always separated.

 

[Cruiser]

That is the perfect size ... I like to put large grain pool filter sand with that size because because the pieces still touch but are always separated.

Is the sand equal in size to your bark? Do you notice much difference between using it vs not?

I mix bark with equal-sized pumice. It drains better and appears to prevent mycelium from becoming too dense.

 

[nuttiest]

Is the sand equal in size to your bark? Do you notice much difference between using it vs not?

I mix bark with equal-sized pumice. It drains better and appears to prevent mycelium from becoming too dense.

No, filter sand is much smaller than perlite, but much larger than play sand. I only use it for nursery containers, because every time I get something nice from the nursery, there are fat white roots and in that bark-sand soil + green time release fertilizer. Is it fat new roots you want to avoid? Use 100% pumice

 

[Cruiser]

No, filter sand is much smaller than perlite, but much larger than play sand. I only use it for nursery containers, because every time I get something nice from the nursery, there are fat white roots and in that bark-sand soil + green time release fertilizer. Is it fat new roots you want to avoid? Use 100% pumice

Nope, fat new roots are welcome.

It's overly dense fungal patches I want to avoid. The bark and fertilizer I use develops rich colonies of it, but if there’s too much, it slows drainage.

 

[Cruiser]

Another 5 gallons of bark was processed in the electric chipper. This time it was chipped twice.

Resulting particle size distribution:
<1/8” (fine)- 8%
1/8-1/4”- 37%
1/4-1/2”- 37%
>1/2”- 18%

-Chipping the bark for a second time goes a little quicker than the first feed.
-Net amount of fine and 1/4-1/2” size particles is the same as when chipping once.
-More 1/8”-1/4” particles were created at the expense of >1/2” particles. This is a good result. Useable bark increased to 74% from 63%.

 

[elijah_moncrieff]

Wow, this is amazing! Ironically I was looking at an electric chipper this morning and I live in a massive ponderosa pine forest so sourcing material is as simple as taking a hike. May I ask what your soil mix is? My thought was to do equal parts APL plus an additional part pine bark or possibly two parts pine bark. I’m growing mostly deciduous trees and a few junipers/pines. Curious what recipe you use and your suggestions.

 

[Gabler]

Wow, this is amazing! Ironically I was looking at an electric chipper this morning and I live in a massive ponderosa pine forest so sourcing material is as simple as taking a hike. May I ask what your soil mix is? My thought was to do equal parts APL plus an additional part pine bark or possibly two parts pine bark. I’m growing mostly deciduous trees and a few junipers/pines. Curious what recipe you use and your suggestions.

For growing, just use perlite, plus your organic component of choice. I also use a bit of coarse vermiculite, so I don't have to water as often. Save the akadama for trees in refinement.

 

[elijah_moncrieff]

Interesting you mention vermiculite, not an ingredient I hear mentioned often but the idea of water retention makes sense! In terms of breakdown how does the vermiculite handle time between repotting?

 

[Cruiser]

Wow, this is amazing! Ironically I was looking at an electric chipper this morning and I live in a massive ponderosa pine forest so sourcing material is as simple as taking a hike. May I ask what your soil mix is? My thought was to do equal parts APL plus an additional part pine bark or possibly two parts pine bark. I’m growing mostly deciduous trees and a few junipers/pines. Curious what recipe you use and your suggestions.

I use pumice and Douglas-fir bark.
Ratios vary. Usually 1:1 (bark: pumice) or 2:1 for shade-tolerant species, most deciduous, and riparian trees.
Pure pumice works too but typically requires more watering.

If you are growing out trees, just bark and/or some other aggregate is fine. Good drainage is key.

 

[elijah_moncrieff]

I use pumice and Douglas-fir bark.
Ratios vary. Usually 1:1 (bark: pumice) or 2:1 for shade-tolerant species, most deciduous, and riparian trees.
Pure pumice works too but typically requires more watering.

If you are growing out trees, just bark and/or some other aggregate is fine. Good drainage is key.

Thank you so much for this! Any particular reason that you choose Fir bark over pine?

 

[Cruiser]

Thank you so much for this! Any particular reason that you choose Fir bark over pine?

Mainly because DF bark is more decay resistant than most pine and many others. It also is shaped differently (more cubical instead of flat). The shape helps promote good drainage and air exchange.

Where are you located? Where there’s ponderosas there’s often Douglas-fir.

 

[elijah_moncrieff]

Mainly because DF bark is more decay resistant than most pine and many others. It also is shaped differently (more cubical instead of flat). The shape helps promote good drainage and air exchange.

Where are you located? Where there’s ponderosas there’s often Douglas-fir.

I’m in northern AZ near Flagstaff, lots of Ponderosa, but not many Doug fur in my area. I can drive ways to get to them though.

 

[elijah_moncrieff]

27 gallons of small nugget df bark. $10.00 from a local landscape supply.
View attachment 545672
The chunks are mostly too big to use for bonsai. Sifting nets some useable particles, but not many; and definitely not worth the time and labor involved.
View attachment 545673

Bark chunks need to be broken up. What is an efficient way to do this?

An electric chipper. (My wife bought this one used for $30.00.) Most are too weak to handle serious tree work, but they can gobble up small branches nicely.
View attachment 545676


I decided to chip and process 10 gallons of bark.
Chipping took 13 minutes. Here is what the bark looked like after. Most pieces were reduced to 1/2” or under.
View attachment 545677


Chipped bark was then sifted through a 1/2” screen.
View attachment 545678
It took 10 minutes. Sifted particles are 1/2”+. Most wood shards were removed at this step.
View attachment 545679
Remaining…
View attachment 545680


Remaining bark sifted through a 1/4” screen.
View attachment 545681
This step took 12 minutes. Sifted bark ranges from 1/4”- 1/2”.
View attachment 545682
Remaining…
View attachment 545683


Remaining bark sifted through 1/8” screen.
View attachment 545684
This time it only took 8 minutes. Sifted bark is 1/8”-1/4”. It looks just like fine-grade orchid bark.
View attachment 545685
Remaining fines…
View attachment 545686

Particle size comparison.
View attachment 545687

RESULTS:

Particle size distribution of chipped small nugget df bark:

<1/8”- 9%

1/8”-1/4”- 26%

1/4”-1/2”- 37%

>1/2”- 28%



Time involved to process 10 gallons

43 minutes total

Chipping- 13 min

1/2” sift- 10 min

1/4” sift- 12 min

1/8” sift- 8 min



Was it worth the effort?

For me, yes. I utilize 1/8” up to 1/2” particle sizes. For 6.3 gallons of sifted product it cost 30-40 minutes of time and about $3.00.

For comparison, 2 gallons of 1/4” df bark ordered from online costs $34.00 plus shipping.

Also, from a non-monetary standpoint I prefer to use df bark as a bonsai substrate. It’s a by-product of the timber industry, is locally sourced, and roots appear to love it.

I am SO grateful I found this post, I was in the same delima and couldn’t afford the cost as I use more bark than most in my growing out media and even a higher percent than most in my refinement mix to cut down my need for akadama. When I read this I bought an electric chipper for around $100 and did the same thing and had amazing results. I know $100 would have bought me enough for this year likely but now I can make my own for years to come and I can ensure I get the particle size I want. What did we do before the internet?! Thank you for the thorough post and sharing this gem of knowledge and ingenuity!

 

[Cruiser]

I am SO grateful I found this post, I was in the same delima and couldn’t afford the cost as I use more bark than most in my growing out media and even a higher percent than most in my refinement mix to cut down my need for akadama. When I read this I bought an electric chipper for around $100 and did the same thing and had amazing results. I know $100 would have bought me enough for this year likely but now I can make my own for years to come and I can ensure I get the particle size I want. What did we do before the internet?! Thank you for the thorough post and sharing this gem of knowledge and ingenuity!

Did you go with ponderosa bark? What particle size(s) does the chipper produce?

 

[elijah_moncrieff]

Did you go with ponderosa bark? What particle size(s) does the chipper produce?

I ended up trying both. Ponderosa bark from the forest, and I found a bag of Fir mulch. The fir bark was $15 a bag and ended up yielding around 7 gallons of chips between 1/4-1/8” in my opinion it was well worth it, and it’s working great in my soil. I do prefer the fir bark since it appears to hold a bit more moisture than the pine. But, I think over time as the pine bark ages a bit more it’ll be the same or similar. I did have to process the larger chips a few times to get them to the size I wanted but it didn’t take much time. Also, I bought the Vivosun chipper if anyone was curious. Additionally, if anyone tries this I strongly suggest wearing a respirator. The dust had my sinuses soo irritated the first day. I learned quick!