Many gardeners say an afternoon with their hands in the dirt leaves them in a better mood, and scientists have been curious about why. One intriguing clue came from a study on mice led by University of Bristol neuroscientist Dr. Chris Lowry. When the mice were treated with a friendly bacterium normally found in soil, it switched on brain cells that make serotonin, a chemical linked to mood. It’s early lab research, not proof that gardening works the same way for people. But anyone who has picked tomatoes off their own plants or watched wildflowers open in the backyard knows the feeling the scientists are trying to explain.These 10 parents and kids show that a family garden grown with real kindness can bring genuine happiness home.