Exterior or Birch plywood

[kevin nee]

I need to make some flower boxes and have plenty of Exterior & Birch plywood which would hold up better. Thanks in advance

[Jim Becker]

Exterior for exterior use.

[John TenEyck]

Exterior or, if that's too ugly for you, get some MDO. Great stuff. Paints beautifully, too.

John

[Frank Drew]

What Jim said; it's the glue, not the wood, used in exterior plywoods prevents degradation and delamination. Marine plywood is maybe the best for all-weather conditions.

[Mel Fulks]

I agree with most of the glue comment but in extremes tests I've done with MDO the WOOD starts to come apart while the
glue firmly holds on. Of course if those edges get protection,that won't happen. You can take cheap construction plywood and use Titebond 2 to glue thin canvas (cotton duck) on it.
Yes, perhaps I've mentioned this before; TRY IT. You can cut ply to size , cloth over size . You can stack and glue all pieces at one time if you put plastic between them.