I have an existing raised bed which is full of tree roots. I've dug out all the dirt from the bed down to the original yard. I want to place a pallet on the ground and cover it with corrugated roofing. Then I will refill the bed on top of the corrugated roofing. I am hoping this will prevent the roots in the ground from getting into the raised bed dirt since there will be a 6" gap due to the pallet. My questions are: Does anyone have any thoughts on this approach and is a 6" gap enough?
