we are putting the boxes on concrete. we have drilled some holes in the bottom. do you think i will need to put plastic down? do you put holes in the plastic so the water can drain through it? will the wood rot?
i used plastic on my raised beds to protect the insides from direct contact with wet soil. yes, you will have to put holes in the plastic where you drilled the holes in the bottom.
make sure though that there is a bit of a gap between the sides where they touch the concrete. if you put a full bottom on the boxes, then just use some scrap wood 