Can't you build up the soil level or even put in a raised bed to give yourself more soil depth? Would be easier to change when the time came. I don't have an open soil border; in my GH, couldn't be doing with it after trying it the 1st year. Used pots or grow bags for a while until I found Marshalls' Grobeds, which are sort of a cross between raised beds and bags that just sit on any flat surface. Get great results from them.
Hope this helps.