Painting inside of bonsai pots

[vincepena23]

Been stusying Bonsai for 4 months now. I have 8 indoor trees and plan on creating bonsai pots of my own, using cement. I see videos on youtube of people making them with molds and wiring. At the end they paint them of course. The inside of the pot as well. I keep wondering what kind of paint they are using. It has to be nontoxic, being the paint won't leech into the soil, once a tree has been planted and watered over and over.

Any advice as to what kind of paint to use? Water based, acrylic?

 

[vincepena23]

Anyone out their?

 

[RJG2]

Nice, resurrecting your own two year old thread!

I haven't done any cement things yet, but do have plans to. Personally, I plan on using a concrete acid stain and not paint.

@Weta had some cool cement pots, and I think he used paint - he can probably give you some tips.

Also, search previous threads on this topic, the are plenty.

 

[penumbra]

Some years ago I partnered with a friend and we made a couple hundred hypertuffa pots. We stained them and then leached them with water for a couple weeks. Paint on cement pots holding soil and roots just never made sense to me.

 

[stubmle]

Given that cement can leech alkaline compounds into the soil over time, I can see an argument for painting the inside of a cement pot. This is a known issue with cement fish ponds- they need to be sealed or lined with an impermeable coating to prevent leeching. Epoxy and rubber seem to be the most common. Given that these coatings are designed to be immersed in water for years after application and do not cause harm to the fish, I'd imagine they would work well for plant containers.
I have a few cement flower pots that are not sealed. I don't use them for bonsai though- mostly annual flowers or tropical plants I overwinter inside. I haven't noticed any issues with them so far but I'd be cautious about putting a valuable tree into them as they are.