I recently got my backyard interlocked and had a stone garden wall installed (6 feet long, 3 feet wide and 15 inches tall). The garden wall is surrounded by interlocking on 3 sides and a wall on the fourth side. The contractor used high performance bedding (HPB) as the base material and ended up filling the bottom of the raised garden with HPB. I believe they did it so it's easier for them to level the whole area. As I didn't know much about gardening then I didn't think it would be a big deal cause there is still 15" space left for garden soil and compost. Moreover the contractor told me that the gravel is useful for drainage. So I went along with their plan.
But now as I am looking up on ways to fill up this garden bed I have found out that many vegetables require deep roots for optimal growth and that filling the bottom of the garden bed with stones is actually bad for plants (e.g. What "gotchas" should I avoid when building a raised garden?). So I am thinking about removing the gravel and replacing it with top soil and organic material. The main concern I have is whether removing the gravel from the bottom of the raised bed would disturb the HPB and interlocking around the garden wall. I would assume that some of the HPB surrounding the garden wall (beneath the tiles) would fall into the empty space that I create by removing HPB from the garden bed floor. But If I replace the removed HPB with soil immediately I am hoping that this disturbance would be minimal ? Is that true ? Is there anything I can do to avoid disturbing the surrounding HPB ?