List Of Gravel Or Rock Under Raised Garden Bed References. This can include compost, or woody material such as logs, dry wood, branches, and leaves. Like the other options, i recommend putting down a barrier first.

Placing gravel under a raised garden bed can improve drainage in the bed. Be sure, however, to carefully consider the raised bed height when building over a gravel surface. You can buy crushed rock and gravel from home improvement centers or rock yards.