Spring has sprung. But you’re dreading the time (and backache) it takes to design and dig a glorious garden. No sweat. Just deck the sills with window boxes—plastic or fiberglass ones work best and cost less. Simply scatter pebbles over the drainage holes in your box, add a layer of potting soil and finish it off with flowers and mulch. When selecting flowers, consider location and time: Bright, showy blooms do best in at least six hours of direct sunlight, and hardy plants like geraniums, petunias and ivy take little effort. Then sit back and enjoy the view.