Richard Evans wrote:
KTTT wrote:

You can use PVC boards, or "plastic wood", from Home Depot. Lowes also
carries a different brand with different characteristics.

The stuff I looked at at Lowe's is prohibitively expensive. Where a 1
x 6 x 8 PT board is under $5, the same size plastic wood is over $32.
They did have some on sale for $23, but still way too expensive.

I came across this on the Web: "If you have to use a wood
preservative to keep wood from rotting, use a copper napthenate
product"

I'll probably go with pine and the CN preservative, assuming I can
find such preservative.

It's true that those pcv stuff is quite expensive. It would be a lot
cheaper to buy pre-made cedar planters. :-)

I too was looking for ideas to make my own wooden containers. For the
same reason, I decided not to use those pcv boards. (But if you later
change your mind for any reason, the brand that Home Depot carries is a
lot lighter and seems a bit stiffer too.)

I was thinking about using 2x untreated pine lumber and cover the inside
with may be two layers of heavy plastic. The paint section in Lowes or
Home Depot has these plastic sheets in various thickness.

You could run the plastic sheet over the top edges of the container, and
use some 1"x2" pine to cover the top sides to make it look nicer.

The outside can be left as it is or painted with exterior paint. That
would make the containers last for at least five years. I think if you
could water proof the inside well enough with plastic sheets, there
would be no need to paint or treat the outside. (Pond liner would be a
good alternative for plastic sheet.)

Well, I abandoned the wooden container idea. It's just too much work to
build two dozens or so 2'x2' containers for me. I ended up with some
cheap plastic planters. But if you prefer a "raised bed" on the deck,
something like a 4'x8' raised bed, pine lumber would be a much better
idea.

Regarding plywood, I would think that it would not work very well unless
you seal the edges real well. The glue would not hold very well after a
season or two in the the rain. Marine plywood would be better since
they use waterproof glue but pricewise it is not a good idea either.

I would not use any preservative on a wooden containers for growing
vegetable, unless it specifically says organic AND safe for growing
vegetables.