I'm wondering if anyone has done this before and has had any success.
I am setting up a dahlia garden 8 x 16 in a spot which used to have
grass. I am digging out the grass and going down about two feet. In
order to retain water I was going to line the bottom with plastic, cut
holes for drainage and then fill up the area with dirt. My two
concerns are, is 2 feet deep enough for a dahlia and even with holes
in the bottom do I run the risk of having the dahlia tubers rot?