On Mar 28, 12:51 pm, "Jonathan" wrote:
I am building two large organic vegetable box gardens - 16 by 4 ft.
and about 3 ft deep.
I was wondering about how concerned I should be about slowing the wood
rotting over time. I am using redwood. I was thinking of lining the
interior with plastic, but I don't want it to leach anything toxic
into the soil. Do I need to be consider a lining, and if so, is there
a kind of plastic that is recommended?

I'd probably line it with 3 mil polyethylene - the kind you can buy as
a drop cloth.
A few years ago, I converted a broken down redwood picnic table to a
garden box.
It lasted about 4 years with no liner. Sorry I did not line it. Now I
just use 20 inch plastic pots. Offhand, I cannot think of any
plastics, with exception of rubber, that might leach toxic materials.