Baking soda neutralizes the ph in the soil and nothing will grow there. I use baking soda in a 6" wide area around all of the edges of my flower beds to keep the grass and weeds from growing into my beds. Just sprinkle it onto the soil so that it covers it lightly. I usually have to do this twice a year - spring and fall.
Hostas, Violas, & Blue Phlox...Consider using a cast-concrete pool for a miniature garden. Because these pools are made to accommodate plumbing, there are already holes in the bottom that allow for drainage.