Hey Newbie. Yes they will rot. That is why I recommended railroad timbers. But now I'm not even sure about them. My neighbors have always used them and has never had a problem that I know of. I'm wondering if maybe she coats them in something first before she uses them . They are coated with kriso and it takes a real long time for them to rot. I wonder if the kriso on them is what J3nn is referring to.The Landscaping timbers are usually treated and want rot as fast also, but I was thinking maybe u shouldn't use them ,because they are treated and the chemicals might get into what you are growing . So SCRATCH that BIG IDEALTo. Hey ! What do you cook in them oven things? ( bread ) Just wondering ?