raised bed questions
I'm looking to perhaps add some raised beds, probably stone or other decorative material, in some parts of my yard.
My concern is cold hardiness in general. Since a raised bed, like a container, has cold exposure on the sides as well as the top, logic would say the root zone of these plants ends up a lot colder in winter than it normally would.
Is there a guideline to this? Or, is there a specific size of a raised bed to where this is no longer an issue?
In other words, if I'm in zone 5b, would a plant JUST hardy to 5b be vulnerable? Should I plant for a zone colder in this case? Is there some rule of thumb here?
Summer heat is also a concern, but could be offset more easily I think with extra irrigation.