If the idea of digging in the dirt has never much appealed to you, consider this: A growing number of studies are finding improved mental and physical health benefits of gardening that extend far beyond the obvious rewards of exercise and fresh air. And in this economy, the free food certainly doesn't hurt. There's no need to dig up your entire backyard, either.

You need only a window box or a few houseplants to see these improvements in your health:

1. Improve your satisfaction with life.

It's hard not to enjoy life when you're surrounded by flowers, vegetables and all the wildlife they attract — and now there's science to back that up. Professors from the University of Texas and Texas A&M asked 298 older adults how they would rate their "zest for life," levels of optimism, and overall resolution and fortitude and found that gardeners had significantly higher scores in all those areas than non-gardeners.

Considering that antidepressant use among adults over 65 has nearly tripled since the 1980s, gardening could be as useful as Prozac for warding off the blues in our aging population.

2. Lower your osteoporosis risk.

It's probably no surprise that gardening, and all the physical activity that goes along with it, leads to weight loss and better overall physical health. But that physical activity can improve your bones as well. In a study of 3,310 older women, researchers from the University of Arkansas found that women involved in yard work and other types of gardening exercises had lower rates of osteoporosis than joggers, swimmers and women who did aerobics.

That likely has to do with the fact that gardening is sort of like weight training, the study authors note; you have to pull weeds, dig holes, carry heavy loads of soil and compost, and do other forms of weight-bearing activities that ward off osteoporosis.

3. Lower your diabetes risk.

One of the primary components of managing diabetes is getting enough physical exercise. Active gardeners easily get more than the recommended 150 minutes per week of exercise, and those who garden just for fun get just slightly less than that, according to research from Kansas State University.

And if you grow food in your garden, you have another diabetes-management tool at your disposal: fresh produce. A number of studies have found that diabetes rates are lower in areas with community gardens, or places where backyard gardening is more common.

4. Better sleep.

The mental health benefits of gardening are so strong that a field of medicine called horticultural therapy has been developed to help people who have psychiatric disorders deal with their conditions. Studies of people with dementia and anxiety have found that gardening helps calm their agitation, leading to better sleep patterns and improved quality of their rest.

There's no reason the rest of us won't benefit, too. Researchers from the International Society for Horticultural Science interviewed 42 people both with cancer and without cancer, and found that all of them used gardening as a coping strategy for stressful life situations. The less we're all stressed out, the better we'll sleep.

This article was written by Emily Main and originally appeared on Rodale.com. It is republished here with permission.

Also on Rodale: Grow your own farm on less than an acre

Inset photo: katerha/Flickr

4 surprising benefits of gardening
Gardening protects your mental and physical health — in case you thought it was just for fun. Here are 4 big ways gardening is good for you.