Scientific research suggests that getting up close and personal with dirt can improve children's mental and physical health.

Washington - When our cherry tomatoes blush red each summer, my son eagerly plucks them from the vine and pops them in his mouth. He points at random plants and proudly declares, "That one's mine!" And occasionally, he yells in panic as the hose from the rain barrel overflows his tiny watering can.

Admittedly, gardening with kids isn't always idyllic.

But even when it's chaotic, it can be tremendously beneficial. Scientific research suggests that getting up close and personal with dirt can improve children's mental and physical health. Gardening can help kids burn off extra energy and control their impulses, develop strong immune systems, and willingly consume more healthy fruits and vegetables. What's not to like?

And despite the gloomy news from studies showing that tweens and teens spend an average of six to nine hours a day on screens, more families with kids are gardening now than 10 years ago. According to the National Gardening Association, gardening in households with children increased by 25 percent from 2008 to 2013, as families have awakened to the hidden benefits of the ancient pastime.

Even when my four-year-old is bouncing off the walls, he visibly relaxes when we head outdoors, finding the self-awareness to avoid stepping on delicate plants. Similarly, my one-year-old stops whining and focuses on drawing in the dirt.

My children aren't alone. The natural stimulation of being outside seems to replenish exhausted minds by practicing self-discipline, re-energizing the part of the brain that controls concentration, checks urges and delays gratification.

A study of 169 girls and boys in a public housing development in Chicago found that girls who had greener views from their apartments did better on tests that measured self-discipline. Of the range in test scores, one-fifth of the variation could be explained by the differences in the "greenness" of the kids' surroundings.

These benefits may be even greater for children with attention-deficit disorder. A survey of 96 families asked parents which activities appeared to decrease their child's symptoms and which seemed to increase them. Parents consistently chose "green" activities as having a positive effect on their child's symptoms.

"Most of us have a pretty significant nature deficit and would be healthier if we could address that deficit by spending a little more of our time in an outdoor setting," says Robert Zarr, founder of Park Rx America and a pediatrician in Washington. Park Rx America encourages doctors and other health providers to "prescribe" time in nature.

And that time in nature may even allow us to use our senses in new ways, experts say.

"It's about planting the plant and watching it grow, but it's also about other things," says Richard Louv, author of Last Child In The Woods and co-founder of the Children & Nature Network. "It's about turning over the rocks. It's about getting your hands muddy and your feet wet. It's about using more of your senses. It's about being in the world."

Gardening combines the general benefits of being outside with the opportunity to tackle a project. My four-year-old proudly waters the blueberry bushes and weeds around the garden fence. He's building his ability to focus as well as his executive function, or capacity to manage information and react to situations. For example, he quickly learned that his watering can will overflow if he doesn't pay attention. And older children can take responsibility for their own green space.

"If the kid has a solitary experience creating his or her own garden, there's a special magic to that," Louv says.