Is anyone using pine bark in their bonsai soil ?

[hemmy]

I have used the bark in substitute of akadama on deciduous material with more frequent repots. I haven’t observed it breaking down and robbing nitrogen as some claim. I’m a fan of using what you have locally because it’s hard to use what you don’t.

Since this was liked recently, I thought I would update. There’s plenty of literature on nitrogen use of bark. But my main (and dwindling west coast supply) was a fine fit bark for orchids. While it didn’t look composted, it was almost certainly aged. Deciduous trees that get the pine bark pumice mix are in development and not fine ramification. Some are in shallow boxes, but not shallower bonsai containers.

But the 2nd year of real Fall I noticed a curious difference between two tridents. The akadama/pumice tree was still green while the bark/pumice (3yrs after potting) started getting Fall color, but rather inconsistently. They froze shortly after so I never got bettter pictures. The next year I fertilized more in the summer and they had similar Fall color.

 

[elijah_moncrieff]

Since this was liked recently, I thought I would update. There’s plenty of literature on nitrogen use of bark. But my main (and dwindling west coast supply) was a fine fit bark for orchids. While it didn’t look composted, it was almost certainly aged. Deciduous trees that get the pine bark pumice mix are in development and not fine ramification. Some are in shallow boxes, but not shallower bonsai containers.

But the 2nd year of real Fall I noticed a curious difference between two tridents. The akadama/pumice tree was still green while the bark/pumice (3yrs after potting) started getting Fall color, but rather inconsistently. They froze shortly after so I never got bettter pictures. The next year I fertilized more in the summer and they had similar Fall color.

This is definitely interesting, thanks for sharing your findings! I’m currently doing some similar trials with different mixes of APL (substituting bark for akadama) using Fir bark, Pine bark, and a mix of 50/50. The Pine bark is aged but not composted, and the Fir bark is composted. I’ll keep an eye out for this and see if it’s different between the three mixes I’m trying.

 

[bpancakes]

Interesting topic! My understanding (without practice) was that wood chips will both suck up AND leech nitrogen, so its not just taking. Based on UCSC master gardener videos on their trees in ground. It is added as a top layer with compost underneath, repeated every year so the wood breaks down beneath the surface. So it isnt entirely mixed in just layered and covered over time leading to a deep mix. Id love to get some hardwood chips, my gut tells me that would be the jam.

 

[elijah_moncrieff]

Interesting topic! My understanding (without practice) was that wood chips will both suck up AND leech nitrogen, so its not just taking. Based on UCSC master gardener videos on their trees in ground. It is added as a top layer with compost underneath, repeated every year so the wood breaks down beneath the surface. So it isnt entirely mixed in just layered and covered over time leading to a deep mix. Id love to get some hardwood chips, my gut tells me that would be the jam.

I have a lace leaf JM that I have had in a regular landscape pot for 6-7 years and used this method. The first round of (fresh hardwood) chips I put on the soil surface when it was planted have finally got to the point of being brown crumbly composted bark. I do believe this has enriched the soil since the occasional earthworm has been spotted in there and likely help to break down the chips. The soil smells like the forest floor and tree is very happy. As far as bonsai goes I’m not sure top dressing would make sense because we repot at a frequency that wouldn’t allow the wood to break down in that time, in addition that the soil microbes in a bonsai pot are different than that of what is found in garden soil. But, I do use bark in my bonsai mix for water retention and my trees seem to grow well.

 

[River's Edge]

What ratio of pine barks with other ingredients in your pre bonsai soil ?

Typically one tries to keep organics below 10% of the mix. I use fir bark for 5% of my overall mix to aid in moisture retention and increase the cation exchange capacity. I am mixing it with pumice, lava, grit and akadama.

 

[DeepSouth]

The ideal ratio is entirely tree and location dependent. Here in Louisiana, I am using 1/3 sifted pine bark, 1/3 haydite, and 1/3 pumice. We have many months of very long, very sunny, and very hot days. The pine bark helps to retain moisture. I have actually found that during repotting, the fine roots often grow into the bark, which is a bit annoying honestly, but clearly there is a reason they do that.

I also fertilize all my trees with Biogold, which keeps a steady (but not overbearing) flow of nitrogen into the soil.

If I was in the Pacific Northwest, I would probably not use any organics at all.