Gardening is an engaging hobby that can provide a host of benefits, some of which may surprise even the most devoted gardeners. For example, the Harvard Medical School notes that just 30 minutes of gardening activities burns 135 calories, making gardening a fun and simple way to incorporate more exercise into your daily routine. In addition, scientists have long proven that gardening releases the hormones serotonin and dopamine in the brain, each of which are associated with improved mood.