Hi, I'm going to try my hand at a grape plant this spring. I'm in Victoria, and my garden is flat, but as most folks in Victoria know, we get a lot of rain. I understand that grapes don't like wet feet. To get around this, I was considering making a small raised bed, and filling it with a very porous, rocky soil, to aid in drainage. Example: a 4X4 square raised bed, about 16 inches high. Is that an appropriate approach? Thanks.