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plays in the dirt

photo by Catherine Castle

About ten years ago my daughter bought me a t-shirt and cap that say, “Plays in the Dirt.” Every gardener should have one, in my opinion. Because playing in the dirt is good for you.


I’ve always contended that gardening is a fantastic stress reliever. At least it has been for me. I always thought it was the result of the physical activity or the satisfaction I got when I looked back at the bare ground I just rid of its noxious weeds or time spent in the sun listening to the birds chirp and the bees hum. Those things play a big part, but it turns out the real reason is hidden in the dirt.


According to an article in the December 2012 Prevention magazine (which I happened to come across as I was culling my magazine pile—yes, I know it’s an old, old magazine. What can I say? I’m a bibliophile), researchers say the secret could lie in the dirt itself. Apparently, there’s a link between a common bacteria (M. vaccae) found in the soil and increased serotonin levels. As gardeners we possibly inhale this bacteria when we dig in the dirt, leaving us less anxious and better able to concentrate.

The drug-like effects of this soil bacteria were discovered by accident about twelve years ago by a doctor named Mary O’Brien. She created a serum out of the bacteria and gave it to lung-cancer patients, in hopes that it might boost their immune systems. Instead, she noticed the hospital patients perked up, felt happier, and had less pain than patients who hadn’t received the bacteria.

Another test with mice, by Dorothy Matthews of The Sage Colleges in Troy, New York, and her colleague Susan Jenks, discovered that mice fed the live bacteria navigated mazes faster than their control counterparts and that the effects of the boost in brain power, while diminished, lasted several weeks.

University of Bristol neuroscientist Christopher Lowry and his colleagues dropped mice into water for five minutes and timed how long it would take for the rodents to stop actively swimming and start floating. Control mice swam for an average of two and a half minutes, while the M. vaccae–injected rodents paddled for four minutes.

I can’t say I feel smarter after gardening, but Lowry’s research might explain the energy boost I get in the garden. That energy that keeps me saying, “I’ll just weed one more row. Fill one more trash bag. Garden one more hour,” long after my original plan of just 30 minutes.  The hubby knows never to believe this mantra, but I keep thinking I’ll accomplish it. And it may also explain why I feel sooo much better when I get out into the garden and work … in spite of the chigger bites, battles with three-foot high weeds, fungal diseases, poison ivy, and those sore muscles I get with marathon, weed-pulling sessions.

I’m sure the researchers are looking for ways to bottle this discovery and turn it into some patented chemical prescription that they will try to sell to us to alleviate our depression or other aliments. After all, you can’t make a profit telling someone to go outside and make a garden.

As for me, I think I’ll stick to just playing in dirt.