First time poster in this forum needing helpful advice on wood after a confusing trip to Lowes.

My project is for an open sides/ends high hoop tunnel and the question about what works well or not well for ground contact, according to people actually doing gardening and not people building decks.

The idea I had was just make the rectangular footprint, grate/rake the sandy soil clean and then fix the lengths and widths with 1 x 6 wood. Then I come to see the 1x6 is sold as 5/4x6 pressure treated, but labeled not for ground contact. The employee who knew the most about it said people use it for raised beds anyway but couldn't recommend it either way. The 4x4 pressure treated which is labeled ok for ground contact is more expensive and not as tall (but nicely wide) and not so attractive due to its price. My plants will be in pots and I am thinking of just covering the bottom double with black weed barrier and using the wood to define the perimeter of the floor -. The tunnel is quite high.

Does this sound ok? Can I get away with the 1 x 6 's which would be set an inch or so into the dirt ... (4x4 would just rest on top I think) and is there anything I should do (like have to paint with something) The only water will be from the heavy rains we always get .... this is not being used to actually contain soil for the plants, only to keep rain off and toss over a shade cloth when necessary, or longer plastic maybe in the winter...which would use the wood to rest on and mostly seal.

Please, any tips would be appreciated! Especially with the low down on what we are paying for with the two different qualities of wood and if painting makes economic sense.

EDIT: My ground is fairly low and the water table high. The blazing sun burns ground bone dry and hot and it rains and soaks, a lot. Probably everyone here can relate ...

This post was edited by PupillaCharites on Thu, Apr 24, 14 at 23:40