In my opinion a terrace area needs to be held back with something substantial, not flimsy planks. The planks would be used to build a concrete wall or line the inside of a rock/brick wall.

Hi mousekakob...you would be wise to consult a person who is into designing/building hillside structures/terraces. I have built retaining walls for myself...thinking they were rugged and well built...and have had them lean out from the pressure of the soil behind pressing out. With clay under your strucures you might find them sliding down hill with the right amount of rain...as clay is very slippery. The higher/steeper your hillside/bank the more problems your going to have with keeping everything in place. Do it right the first time...and keep things simple...Franklin

Yeah, thought about the weight of the soil thing after posting last night. Unfortunatly, I can't afford to consult a professional on this right now. If we do it, we're going to have to do it on our own. Brotherinlaw was down to visit a few weekends ago. he reccomended getting the landscaping timbers from a landscape supplieir instead of the local big hardware store. Will have to look into the cost difference.

I can still do the lasagna bedding thing though, inside the different levels.

You still might want to be careful around that poison ivy, I understand you can develop an allergic reaction, even if you're currently not allergic.

-S