JohnFranklin - Zone 7b
Yamadori
Does anyone know if glazed pots present any advantage over unglazed pots or vice versa?
Bonsai Pots - Glazed vs. UnGlazed
- Thread starter JohnFranklin - Zone 7b
- Start date
MSU JBoots
Shohin
Not that I know off. I know generally glazed are traditionally for deciduous and unglazed for conifers.
jeremy_norbury
Omono
I believe there is zero difference...it is pure aesthetics.
rockm
Spuds Moyogi
There are no advantages or disadvantages to either, comparatively, only aesthetics and personal taste. There are some who still believe the myth that unglazed pots "breathe" or allow moisture to move through the interior to the exterior of pot walls because of porosity in the clay, while glazed pots can't do that because the glaze blocks it. None of that is really true for the high fired stoneware used in quality bonsai pots.
On a similar note… I know that genearally the inside of a glazed pot remains unglazed but I have come across a few pots that are glazed on the inside as well. Is there a downside to this? I have a very nice Chinese mokko that was reduction fire and the finish is both inside and out. Any idea what the deal is with this?
Wires_Guy_wires
Imperial Masterpiece
That's very much true. I am a big fan of breathing terra cotta pots though, and those definitely breathe and sweat if they are unglazed. That trait alone makes them superior above all else when it comes to plant health.
Aesthetically ugly, sure, but darn good for my soil biome and by proxy also the plants themselves.
I wouldn't mind seeing more well designed terra cotta pots being used as bonsai pots. I mean, people out there are using metal, potless pots, and all kinds of materials. I think the time has come for terra cotta to follow the trend of being prettier than just bowl designs.
Unless your pot is a glassy porcelain it WILL absorb and move a lot of moisture. As high as 8% on some Tokoname pots. Both glazed and unglazed pots will absorb moisture, but if a glazed surface is impermeable then it will not vent as well as an unglazed pot. Most glazed surfaces are not completely impermeable. Best to think of pots as a sponge.
In Tokoname the potters try to balance absorption and maturity and they view low absorption negatively 'yakishimeta'.
penumbra
Imperial Masterpiece
I believe the difference is minimal but present. Not enough to make any difference in plant health IMO. As to the traditional aspect of deciduous in glazed and conifers in unglazed, I don't subscribe. If I had my bonsai in display at a show I would probably adhere. And I must admit that a pine in a dark unglazed pot can really look fabulous and more often better than in a glazed pot. Other conifers like juniper and hinoki I can see either way but a hinoki in a blue glazed pot is awesome.
BrightsideB
Omono
Does the entire pot look this way? Even the bottom of the feet? Could just be the way the clay reacts in a certain atmosphere and temperature.
Here’s a couple examples of the difference atmosphere can do. Pretty wild!
Yes, the entire pot is like that. The finish is similar to the salt fired finish. You can see below that even the bottoms of the feet carry the same finish.
D
Deleted member 47471
Guest
I’m beginning to like Terra cotta more now. Other than using AF for specific reasons, I think I’m going to use Terra cotta during development for trees moving forward. They look nice and clean. Danny Coffey has convinced me of this fully now.
rockm
Spuds Moyogi
Thanks! Didn't know this. Not a potter, obviously.
penumbra
Imperial Masterpiece
I love terracotta pots but in my climate the are lucky to last a few years.
ForrestW
Mame
I am always grateful for what you share in these, and I love your clay bodies. Can you share how this is measured or tested? The only test I am familiar is the 6 hour absorption test-- which in my opinion is still somewhat scientifically flawed. (weigh a pot. clay sample boil for 6 hours, quench in cool water, then weigh again)
Gabler
Masterpiece
But they shatter in the cold. It only works for tropicals.
Wires_Guy_wires
Imperial Masterpiece
No they don't.
Mine are going strong for 10+ years
Gabler
Masterpiece
Then I need to find better terra cotta.
Me too. I can post photos of the pile of terracotta shards I have from pots that didn’t survive the numerous freeze/thaw cycles here in Maine
River's Edge
Masterpiece
Provides opportunity to match foliage and flower color in display. Expands choice.
May be some evaporation, heat transfer/insulation variables.
BrightsideB
Omono
What people sell as terracotta pots are just low fire earthenware clay bodies for the most part. They have a terracotta color. They can really be straight garbage. Also they aren’t all the same either. There are terracotta pots that can withstand freezing better than others. I’ve made some and they are way better quality than most the mass produced ones. I bet they can easily last a decade without a crack here in north Georgia where it is pretty temperate. It really just depends on the clay body in conjunction to what it is fired to. I wouldn’t use them for my tree’s though. Better off with flats and pond baskets in my opinion. Even colanders or grow bags.
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