Gardening comes with a host of well-documented health benefits. The most obvious of them has to do with the fact that a bit of gardening is done outdoors. Exposure to sunlight increases vitamin D, which is good for bones, teeth and muscles. And speaking of muscles, gardening is a great form of low-impact, high-impact exercise if you're lifting huge pots or wheelbarrows of dirt around.
Watering your garden is a good thing, but since many diseases need water just as much as plants, the way they do it makes a big difference. Many pathogens in soil and air need water to move, grow, and reproduce. To avoid giving these diseases an environment they love, choose irrigation methods that limit moisture in a plant's foliage. Soak hoses and drip irrigation achieve this.
If you water by hand, keep the leaves out of the way while watering the roots.