Every daylily I have except the sales plants and seedlings are in raised beds. The sales plants are in pots and the seedlings are in the ground. The new box I just completed in the display area will have three gallon pots in it. After the Regional next year they will be removed, divided, and repotted for the sales area because they will all be 2011,12, and 2013 daylilies.The rest of the boxes have the pine bark mix in them.
The bottom of the box is the same as the sides, treated 2X10X8 foot long. Plywood or decking board will not last long enough. The box is on treated 4X4s four foot apart.
This is a 60X4' box. A 20x4' box cost about $300 for lumber and screws from Lowes.