Reducing from Grow Containers to Pots

[bobbywett]

Hello Folks,

I’m getting ready to repot a dozen or so of my pre-bonsai into pots next spring. I have a couple of questions though.

1. Can I reduce the root mass radically in order to fit some trees into a finished sized pot, or is there an in between size I should be shooting for? Most of my trees have been in their current containers for 2-4 years and I happy with their trunk diameter.
2. I like the idea of using clay or terracotta over plastic or mica. Do they make clay or terracotta pots that are deep enough to help me slowly reduce the root mass, or can I just purchase finish pots and not worry about slowly reducing the roots?
3. Does anyone know of a source to purchase clay or terracotta pots that won’t break the bank.

Thanks so much for any help,

Bobby

 

[Leo in N E Illinois]

Generally, for deciduous trees, you can be pretty aggressive in flattening out the root system. In one go the maple in the plastic tray could be moved to a "real" bonsai pot. Perhaps a pot 2 to 3 inches deep and slightly less width and length compared to its training container. Similar with the Ginkgo. You can be aggressive in pruning both the branches and the roots on the same day as you do the repotting. If the tree is healthy and vigorous from the previous growing season, removing 50 % to 75% or more of the root system is no problem. Very drastic root pruning will slow growth for the upcoming growing season, but the tree will respond well and the following growing season can be quite good. Generally once you have the root system "shaped" for the bonsai pots, on subsequent repotting, you don't have to be drastic with your root pruning. Subsequent repotting can be "just a little off the edges and bottom".

Pines, junipers and most conifers, we move more slowly with. As a general rule you do not remove more than 25% of the roots at any one time. The year that you prune the roots you generally do not do any pruning of the foliage. This is a "generalized" rule. Once you have more experience, you will know where you can get away with being more aggressive. But if I was planning on doing root work on a juniper or pine, I would not prune the foliage for 5 months before the repotting, and would not do any pruning for 12 months afterwards. I also do not repot my conifers very often, once every 3 years to once every 10 years. Conifers do not respond like deciduous trees to root work. They respond much more slowly.

 

[leatherback]

removing 50 % to 75% or more of the root system is no problem.

Fully agree with @Leo in N E Illinois here.

As an example, a zelkova I worked on today, part of a large forest I took apart this weekend.

 

[bobbywett]

Generally, for deciduous trees, you can be pretty aggressive in flattening out the root system. In one go the maple in the plastic tray could be moved to a "real" bonsai pot. Perhaps a pot 2 to 3 inches deep and slightly less width and length compared to its training container. Similar with the Ginkgo. You can be aggressive in pruning both the branches and the roots on the same day as you do the repotting. If the tree is healthy and vigorous from the previous growing season, removing 50 % to 75% or more of the root system is no problem. Very drastic root pruning will slow growth for the upcoming growing season, but the tree will respond well and the following growing season can be quite good. Generally once you have the root system "shaped" for the bonsai pots, on subsequent repotting, you don't have to be drastic with your root pruning. Subsequent repotting can be "just a little off the edges and bottom".

Pines, junipers and most conifers, we move more slowly with. As a general rule you do not remove more than 25% of the roots at any one time. The year that you prune the roots you generally do not do any pruning of the foliage. This is a "generalized" rule. Once you have more experience, you will know where you can get away with being more aggressive. But if I was planning on doing root work on a juniper or pine, I would not prune the foliage for 5 months before the repotting, and would not do any pruning for 12 months afterwards. I also do not repot my conifers very often, once every 3 years to once every 10 years. Conifers do not respond like deciduous trees to root work. They respond much more slowly.

Thanks you. That’s a nice summary of what I was trying to understand.

 

[bobbywett]

Fully agree with @Leo in N E Illinois here.

As an example, a zelkova I worked on today, part of a large forest I took apart this weekend.

View attachment 343184
View attachment 343183

Thank you

 

[River's Edge]

If you decide to make use of terra cotta pots for transition I would suggest selecting the wider shorter style used for Azalea, bulbs and succulents. Typically they are available in several sizes with suitable depth to adjust root balls. I prefer 10 inch diameter with 6 inch depth for this purpose. I have found the pots produced in Italy are less prone to cracking from freeze thaw. I would also suggest modifying these pots by adding additional drainage to the bottom, and cutting some small slots in the bottom rim to allow air/water movement under the bottom. The additional holes also aid tying in the trees. Simple cutting wheel on grinder or Dremel will score the rim. Here are a couple of pictures to show shape and modifications. Extra holes are easily seen, the black arrows point out the grooves cut in the bottom rim to aid drainage and air movement under the pot. One of the larger nurseries in your are should be willing to special order a group or provide a discount for bulk purchase.

 

[bobbywett]

If you decide to make use of terra cotta pots for transition I would suggest selecting the wider shorter style used for Azalea, bulbs and succulents. Typically they are available in several sizes with suitable depth to adjust root balls. I prefer 10 inch diameter with 6 inch depth for this purpose. I have found the pots produced in Italy are less prone to cracking from freeze thaw. I would also suggest modifying these pots by adding additional drainage to the bottom, and cutting some small slots in the bottom rim to allow air/water movement under the bottom. The additional holes also aid tying in the trees. Simple cutting wheel on grinder or Dremel will score the rim. Here are a couple of pictures to show shape and modifications. Extra holes are easily seen, the black arrows point out the grooves cut in the bottom rim to aid drainage and air movement under the pot. One of the larger nurseries in your are should be willing to special order a group or provide a discount for bulk purchase.

View attachment 343203View attachment 343204

That’s exactly what I was looking for. Thank you

 

[Shibui]

In most cases I just reduce roots in one go as mentioned by @Leo in N E Illinois
If the trees still need development or more ramification I use an intermediate pot, not because of the roots but because slightly smaller slows growth and gives shorter internodes so better ramification in the final phases of branch and apex development. Otherwise my trees grow straight from the grow pots into the bonsai trays.
Most species will cope with root reduction of 75%. I usually find they shoot away as if nothing happened and often with better growth than the year before as they develop lots of new roots after root pruning.
If you use terracotta pots you will probably need to allow for the increased water needs. Terracotta absorbs water and evaporates it to the surrounding air much more than plastic or stoneware pots.

 

[bobbywett]

Thank you

 

[Grovic]

Hello Folks,

I’m getting ready to repot a dozen or so of my pre-bonsai into pots next spring. I have a couple of questions though.

1. Can I reduce the root mass radically in order to fit some trees into a finished sized pot, or is there an in between size I should be shooting for? Most of my trees have been in their current containers for 2-4 years and I happy with their trunk diameter.
2. I like the idea of using clay or terracotta over plastic or mica. Do they make clay or terracotta pots that are deep enough to help me slowly reduce the root mass, or can I just purchase finish pots and not worry about slowly reducing the roots?
3. Does anyone know of a source to purchase clay or terracotta pots that won’t break the bank.

Thanks so much for any help,

Bobby

I like your trees. Terracotta pots are relatively cheap, and I think they're definitely better looking than plastic nursery pots. I'd recommend you to have a look at your local home depot and lowe's and loolk for "Azalea terracotta pots" or "terracotta half pots". For price, last Saturday I got four 5.5" pots for about $4.00 each. They also had 8.5 inchers for about $7.50 I think, and they were sold out on other sizes (I saw a price tag for a 10", but don't remember the price), but I know they sell them as well.
Very important: physically go to the store, their online stock is not updated that often and they don't have all their stock listed, also the names can be different sometimes.

 

[sorce]

There is nothing cheaper, better for roots, or longer lasting than these.

Those Pot Materials!

Tired of going downstairs to pick up trees that test gravity in the wind, and understanding the benefits of colanders, I decided to solve a couple problems. Crappy pots, and crappy broken pots! One 4in clay completely destroyed, in a sock holding it together. Ham containers, small nursery...

www.bonsainut.com

They won't last long......

They'll last....



Sorce

 

[bobbywett]

I like your trees. Terracotta pots are relatively cheap, and I think they're definitely better looking than plastic nursery pots. I'd recommend you to have a look at your local home depot and lowe's and loolk for "Azalea terracotta pots" or "terracotta half pots". For price, last Saturday I got four 5.5" pots for about $4.00 each. They also had 8.5 inchers for about $7.50 I think, and they were sold out on other sizes (I saw a price tag for a 10", but don't remember the price), but I know they sell them as well.
Very important: physically go to the store, their online stock is not updated that often and they don't have all their stock listed, also the names can be different sometimes.

Thank You!

I wonder if yixing clay pots would be better and if they’re affordable?

 

[sorce]

yixing clay pots

This is a "band-aid" term, "kleenex"....

It's an idea more than a known exact.

What is Yixing Clay?
Traditionally, it is used for teapots, and is porous.
It could be frost proof or not.

It has become "buzzword", "marketable", etc etc...

So though I can't make any solid statements, there are things to consider.

I would only consider antique ones any good, and only for shows and above freezing.

Sorce

 

[Grovic]

Thank You!

I wonder if yixing clay pots would be better and if they’re affordable?

It depends on what you call affordable, they'll be more expensive than terracotta pots for sure, and there are lots of different quality ranges (and prices).

 

[bobbywett]

It depends on what you call affordable, they'll be more expensive than terracotta pots for sure, and there are lots of different quality ranges (and prices).

Do you know of any good sources?

 

[River's Edge]

This is a "band-aid" term, "kleenex"....

It's an idea more than a known exact.

What is Yixing Clay?
Traditionally, it is used for teapots, and is porous.
It could be frost proof or not.

It has become "buzzword", "marketable", etc etc...

So though I can't make any solid statements, there are things to consider.

I would only consider antique ones any good, and only for shows and above freezing.

Sorce

Right on. Consider the source! There is a wide range of quality and price range. Cheap is usually just that. The term is meaningless without knowledge of the specific clay quality and process, not to mention level of craftsmanship! Marketing improvements can be deceiving.

 

[Grovic]

Do you know of any good sources?

Only the most common sources. although I don't know how their prices compare:

Bonsai tools, bonsai pots, bonsai accessories, rectangle bonsai pots, square bonsai pots, round bonsai pots, oval bonsai pots, plastic bonsai pots, ceramic bonsai pots, earth bonsai pots, natural bonsai pots, unglazed bonsai pots

Bonsai tools, bonsai pots, bonsai accessories, rectangle bonsai pots, square bonsai pots, round bonsai pots, oval bonsai pots, plastic bonsai pots, ceramic bonsai pots, earth bonsai pots, natural bonsai pots, unglazed bonsai pots

www.easternleaf.com

Chinese Pottery - Unglazed Oval Pots

Chinese Pottery - Unglazed Oval Pots

www.bonsaiboy.com

BONSAI POTS has a huge selection of ceramic bonsai pots

Bonsai Pots offers a collection of both glazed and unglazed bonsai pots. Shapes include lotus, oval, and rectangle pots. Find the perfect ceramic container.

brusselsbonsai.com

 

[bobbywett]

Only the most common sources. although I don't know how their prices compare:

Bonsai tools, bonsai pots, bonsai accessories, rectangle bonsai pots, square bonsai pots, round bonsai pots, oval bonsai pots, plastic bonsai pots, ceramic bonsai pots, earth bonsai pots, natural bonsai pots, unglazed bonsai pots

Bonsai tools, bonsai pots, bonsai accessories, rectangle bonsai pots, square bonsai pots, round bonsai pots, oval bonsai pots, plastic bonsai pots, ceramic bonsai pots, earth bonsai pots, natural bonsai pots, unglazed bonsai pots

www.easternleaf.com

Chinese Pottery - Unglazed Oval Pots

Chinese Pottery - Unglazed Oval Pots

www.bonsaiboy.com

BONSAI POTS has a huge selection of ceramic bonsai pots

Bonsai Pots offers a collection of both glazed and unglazed bonsai pots. Shapes include lotus, oval, and rectangle pots. Find the perfect ceramic container.

brusselsbonsai.com

Thank You

 

[Paradox]

@bobbywett
When transitioning from a first training or acclimation pot to a more traditional bonsai pot, I prefer to use a larger bonsai shaped plastic training pot such as

Rectangle Shallow Plastic Bonsai Training Pots

Our plastic bonsai pots are perfect for almost every type of bonsai. These pots feature a traditional rectangle bonsai pot shape. Made of a heavy duty brown plastic, they're able to withstand different types of weather and are perfect for both indoor and outdoor use. Each pot has drainage holes...

www.superflybonsai.com

The come in different sizes but are a bit bigger and deeper than a typical ceramic "finished" bonsai pot and are, in my opinion a good transition from the initial post nursery container training pot.
If you go from the deep square/rectangular training pot to a round terra cotta pot, you are really just changing the shape, you really aren't doing anything to transition to a shallower pot.

 

[bobbywett]

@bobbywett
When transitioning from a first training or acclimation pot to a more traditional bonsai pot, I prefer to use a larger bonsai shaped plastic training pot such as

Rectangle Shallow Plastic Bonsai Training Pots

Our plastic bonsai pots are perfect for almost every type of bonsai. These pots feature a traditional rectangle bonsai pot shape. Made of a heavy duty brown plastic, they're able to withstand different types of weather and are perfect for both indoor and outdoor use. Each pot has drainage holes...

www.superflybonsai.com

The come in different sizes but are a bit bigger and deeper than a typical ceramic "finished" bonsai pot and are, in my opinion a good transition from the initial post nursery container training pot.
If you go from the deep square/rectangular training pot to a round terra cotta pot, you are really just changing the shape, you really aren't doing anything to transition to a shallower pot.

So if A bonsai is taken directly from a nursery grow container to a finished size bonsai pot will it suffer any ill effects. I mean other than slower growth of the trunk?