Question
I want to make a planter box for all my outdoor bug eat like the pitcher plants and flytraps. I am here in Portland Oregon. but I am not sure how shallow I can make it so the plants will do well in the winter. also should I make it drain or use some sort of tray to keep the soil wet always? I could use a pond liner 1/2 the way up so the water stays put but can flow out when it is 1/2 the way up the soil.

Answer
The depth of your planter depends mostly on how large your plants are.  If they're still small, a depth of 6-8 inches is sufficient.  If your plants are large, consider 12 inches or more.  Always use pots that drains. Never use undraining pots because this can lead to unhealthy soil.  Use a large tray to let your pot sit in water and keep the soil constantly moist.  Visit our photo gallery for examples of how we maintain our plants at the nursery:
http://www.cobrapant.com/gallery

Good growing!
Jacob Farin