Root oxygenation and container choice

[Vance Wood]

Check out my avatar (left) These are the three sizes of my bonsai training planter I used to make and sell until the cost of material and having my patent ripped off by foreign countries who could produce alternitives and rip-offs cheaper.

 

[Paradox]

I use an anderson flat when as a first pot for larger trees then downsize to larger plastic training pots then down to an appropriate sized bonsai pot for yard display.

The main factor in aeration is soil composition and particle size. A larger, looser particle size (ie lava, pumice) will allow more air flow than potting soil

 

[Lars Grimm]

Yes. But it has nothing to do with drainage

Yes, I am aware it doesn't help drainage (the opposite), but I still hear it referred to as the drainage layer. Maybe we should say 'drainage' in quotes always =)

 

[Lars Grimm]

Check out my avatar (left) These are the three sizes of my bonsai training planter I used to make and sell until the cost of material and having my patent ripped off by foreign countries who could produce alternitives and rip-offs cheaper.

I remember seeing those great boxes a long time ago. I couldn't replicate with your level of craftmanship, but they are very nice.

 

[M. Frary]

No wooden boxes being used here.
Colanders or colander type pots.
For all trees.
Conifer and deciduous alike.

 

[Underdog]

Here are some of my hillbilly methods that work for me.
Anderson flat and cut down milk crate lined with screen in a box with open bottoms.
I like the 1.50 plastic pond baskets and often double them up to reduce hole size and flex. I keep thinking about trying to cut them down shorter. You can also not fill them so deep in some cases but...

Sorry you got ripped off Vance.

 

[penumbra]

From this post you clearly see it is a matter of preference. I use wood boxes for my largest pieces and forest plantings. I use Anderson Flats for group plantings for seedlings and smaller plants. I have used milk crates and bulb crates. I use lots of pond pots for just about everything else. They come in many different sizes and can be had affordably. Lowes has the best price on the larger ones.

 

[Cable]

No wooden boxes being used here.
Colanders or colander type pots.
For all trees.
Conifer and deciduous alike.

Same here. I have most of mine in pond baskets. Pretty much everything in them is thriving. I like them for the air pruning, ease of moving them around (solid and have a good lip), and the fact that they fit well on my benches (like Wendy's hamburgers on a griddle, baby!).

 

[Lars Grimm]

I should be clear that I have no idea if pond baskets are better for oxygenation of the roots or how they impact health vs other containers. I just like them because the roots grow to the edge of the pond baskets and stop so you get a good mass of fine roots, none of which are circling. So much easier than dealing with coiling roots. They are somewhat flimsy but you should be lifting from the bottom anyway. Also, my Anderson pots hardly nest so I cant double up. The best would surely be a wooden box with mesh sides and bottom but more difficult and pricey to build. Also should point out that anything I have in a pond basket is probably 'too small' for most to bother with building a grow box. I am using them as replacements for 4in and 1-3 gallon pots.

I wonder why your Anderson flats don't nest well. Here is a picture of a bunch of mine just stacked up. They came shipped this way.

 

[Forsoothe!]

Yes, it inhibits drainage, but shouldn't it improve aeration? I assume they are related, but not definitively mutually exclusive.

Yes, related, but the aeration is not to supply O to the plant, it is to provide a passageway for gasses in soil to escape. Soggy soil interferes with that, as does compaction. Soil doesn't compact by itself. It shifts around due to watering and over time the particles of whatever medium you use tumble into the empty spaces below them until they can't can move at all.

 

[BubblePopScott]

I'm going to give an air pot a go. One benefit of wooden boxes - you can screw into it for anchors for wire etc really helpful

 

[Lars Grimm]

Yes, related, but the aeration is not to supply O to the plant, it is to provide a passageway for gasses in soil to escape. Soggy soil interferes with that, as does compaction. Soil doesn't compact by itself. It shifts around due to watering and over time the particles of whatever medium you use tumble into the empty spaces below them until they can't can move at all.

Thanks. Presumably the depth of soil matters as well. A deeper pot will benefit more from gas capable of escaping above and below than a shallower pot will.

 

[Ohmy222]

I wonder why your Anderson flats don't nest well. Here is a picture of a bunch of mine just stacked up. They came shipped this way.

View attachment 276874

Yes. I was referring to the post above saying they double up their flats. I was pointing out what you illustrated. That is why the shipping is so expensive too.

 

[River's Edge]

Hi All,

I was listening to Bjorn's end of year podcast and he was discussing the different types of containers used for growing pre-bonsai/rough stock (specifically not finished bonsai). He made the comment that wooden containers are the best in terms of providing root oxygenation (I'm paraphrasing here). This got me thinking, as I have heard this statement very frequently from others as well.

When most of us build wooden boxes, we leave big open spaces at the bottom that are covered up with mesh, screen, or some other porous material that keeps the soil in place but allows drainage/aeration. Although wood may be slightly more permeable to air than clay, plastic, metal, etc, it seems as if the material is far less important than the exposure surface area. The top is completely exposed to the air in all containers, but typically a ceramic pot has only a few drainage holes on the bottom which dramatically limits exposure. To me, this suggests that an Anderson flat which is filled with open spaces on the bottom should perform as well or likely even superior to a wooden box in terms of aeration (depending on the wooden box base design) and a pond basket should be the best of all.

There are other reasons to choose a wooden box, such as aesthetics or the ability to customize the size, but it appears as if the material itself is likely a marginal component at best.

Thoughts as always are appreciated.

Sincerely,
Lars

I believe Root oxygenation is primarily affected by particle size, particle composition and particle shape as it affects air space and possible moisture retention. Adequate drainage is another key factor!
Wood is more effective than plastic insulating temperature swings and adds some moisture retention. This In itself improves root growth conditions. The primary reoxegenation of the roots occurs as the water flushes down and drains out with the particle spaces being refreshed with new moisture, air and nutrients. Perhaps these comments may help to frame the discussion.
To me the main advantage to wood is the moderating qualities, plastic heats and or cools quickly, hold no residual moisture.

 

[River's Edge]

I wonder why your Anderson flats don't nest well. Here is a picture of a bunch of mine just stacked up. They came shipped this way.

View attachment 276874

The vertical stubs in the corner are to stiffen the frame and prevent crushing /twisting in shipping and repeated use. In older versions these problems existed. Now that the flat is stiffer it is sturdier and lasts longer. A trade off! I use both wooden boxes and anderson flats. The Andersen flats are far more economical for me when purchased in bulk. I picked them up at the manufacturer for bulk pricing approximately $2.50 USD each. Bought a pallet ( believe that was 175 or so) Cannot build a wooden box for close to that and they do not last as long!
I'd they nest pretty well actually. Here is a group of 100 prepared for spring. Already have a drainage layer and 1 inch of bonsai soil in each one with wires ready to tie in the new tree's on repot.
I modify each flat by drilling small holes one each side to improve drainage if placed on a less permeable surface. Four or five 1/4 holes per side at the bottom level.

 

[Lars Grimm]

The vertical stubs in the corner are to stiffen the frame and prevent crushing /twisting in shipping and repeated use. In older versions these problems existed. Now that the flat is stiffer it is sturdier and lasts longer. A trade off! I use both wooden boxes and anderson flats. The Andersen flats are far more economical for me when purchased in bulk. I picked them up at the manufacturer for bulk pricing approximately $2.50 USD each. Bought a pallet ( believe that was 175 or so) Cannot build a wooden box for close to that and they do not last as long!
I'd they nest pretty well actually. Here is a group of 100 prepared for spring. Already have a drainage layer and 1 inch of bonsai soil in each one with wires ready to tie in the new tree's on repot.
I modify each flat by drilling small holes one each side to improve drainage if placed on a less permeable surface. Four or five 1/4 holes per side at the bottom level.

You are really organized! That’s inspiration.

 

[River's Edge]

You are really organized! That’s inspiration.

Just a coincidence. It is not always that way. Expecting back surgery shortly so anything i can do ahead of time to make repotting season easier is needed. Expect to be slowed down for a bit afterwards. Sifting is a pain after 40 bags each of pumice, akadama, lava and granite grit. Fortunately my supplies are similar in particle size and not a lot of fines. The flats above are for JBP, JRP, Zelkova, JM and Trident that have reached basic trunk size and i will be starting on taper and primary branching for the next stage.

 

[Japonicus]

Where do you guys get you Anderson flats? I've looked, but can't find them at a reasonable price.

StackPath

scroll down to Anderson Flats

 

[leatherback]

Roots get most of their oxygen by cleaving it from H2O.

I think you have misunderstood this. Or else it is ground breaking news.

 

[leatherback]

There are other reasons to choose a wooden box, such as aesthetics or the ability to customize the size, but it appears as if the material itself is likely a marginal component at best.

One thing I could imagine that wood has as a benefit.. It is a reasonable insulator. As such, the outside of the container does not warm up as fast as plastic / ceramic pots. I would imagine this affects roothealth.