Good idea if you have rock solid ground that is hard to dig up. If you don't cover the holes you can use them for herbs & annuals. also lined with weed barrier cloth & used rebar in several places for stability. It makes maintenence super easy.
What a great idea for some serious green bean growing. This would also work for strawberries, peas, grapes and possibly squash varieties. Basically, anything that can grow vertically! - My Gardening Path