Human beings generally feel happier and more optimistic in surroundings with plenty of plants and nature. Consider a survey conducted at four San Francisco Bay Area hospitals. In the survey, 79 percent of patients said they felt more relaxed and calm, 19 percent felt more positive, and 25 percent felt refreshed and stronger after spending time in a garden.
Flowers also evoke positive emotions. For example, in a 2005 study, women who received flowers reported more positive moods three days later. Elderly patients who received flowers also reported brighter moods and improved episodic memory.
While you may only need to place a plant on the windowsill at home to help create a more soothing environment, you can increase happy feelings even more through gardening. Gardening reminds us of our connection to nature, and helps us focus on the bigger picture, which can alleviate symptoms of depression. Also, the physical aspect of gardening releases feel-good chemicals in the brain such as serotonin and dopamine. Finally, working with soil makes us happier. A 2007 study found a bacterium in soil called Mycobacterium vaccae triggers the release of serotonin, which lifts mood and reduces anxiety.