Greetings. I am a new gardener with 2 years gardening experience. I have a small 15x30 fenced in garden and would like to use the fence as a support for grapes. My problem is that my soil is clay and tends to hold water a little too well. I was considering digging a 3 foot deep trench and filling it with a soil mixture that would drain better. And then raise the bed another foot or so. Would this configuration work for the root system like that of a grape plant?