What type of inside for a brick planter box?

[Solrosen]

Hello!
I'm building an H-shaped planter box with concrete blocks. It will be plastered and painted on the outside, BUT what surface should I use on the inside?
(It will be filled with planting soil and is situated in a fairly sunny/dry spot with well-drained bottom/foundation. About 60 cm high)

Regards
Joel

 

[Solrosen]

...continues with own suggestions:
- Construction plastic?
- Isopalmatta (blue/black with knobs)?
- Only plaster?
- Plaster and paint, like outside?
- Plaster + cold asphalt?

...help! ;-)

 

[ylven]

My first thought is Platon mat, but then I thought it might not be necessary. I strongly advise against kallasfalt and building plastic. Perhaps add ground insulation as a suggestion if you intend to make a hotbed. I think plastering on the inside is wasted effort.

Note that I only have opinions on the matter, no direct experience with a brick-plastered planter, just from bricklaying, plastering, and planters!

 

[Solrosen]

Thanks, we'll skip kallafalt and construction plastic.
"The box" is like an elevated garden bed, without a roof, not exactly a hotbed or cold frame.
How about lining the inner walls with 3 cm insulation boards? We don’t want too much moisture migration in the wall since it will be watered quite a bit.
Is a Platon mat perhaps a better alternative than insulation boards?

 

[mrVoodoo]

If it's just for the moisture migration, maybe it would work to apply a couple of layers of waterproofing on the inside?

 

[Krawk]

//..I directly advise against cold asphalt and construction plastic...//

Why would cold asphalt be bad? It sounds convenient and effective. There shouldn't be any problems with it trapping moisture since it's a flower box? Or have I missed something?

 

[Solrosen]

Ok, if we turn the tables: Suppose a mortared retaining wall, with backfill/soil behind it. What does the inside surface look like? ;-)