Thanks for the good info, Guy. I have been considering putting in a keyhole garden here in town. Think of the space that I wouldn't have to mow!!
I think all I need is some blocks for the outside wall and a load of horse manure. I've got plenty of cardboard, newspaper & leaves, as well as some old tree that didn't get turned into a hugelbed last year. I'm sure I can get access to a quantity of coffee grounds and egg shells at the restaurant where my son worked for so many years. A keyhole garden should keep me well stocked with salad vegetables and might even have room for a few strawberry plants. What about cucumber? If I put in a trellis ... and perhaps some peas ...
While I was at YouTube, I took time to watch a few of the videos on making self watering planters. Since I spend my time in several different places during the growing season, lack of watering is my biggest drawback. Time to rummage in the garage to see what sorts of containers I have that can be repurposed. I know there is an old dresser that I was planning to lay on its back and fill with dirt, while setting the drawers in various spots as planters too.