Planting Edmonds is a monthly column written by and for gardeners.

What Edmonds gardeners know instinctively — that gardening is healthy — has its basis in science.

When I first began working on this article, I read study after study showing what a profound impact it has on our health to dig in soil, eat fresh-grown vegetables, explore the forest and immerse ourselves in greenery.

Let’s first look at gardening. Horticultural therapy has been popular since the 1970s, but gardeners have known for centuries that digging in the dirt is therapeutic. Getting your hands dirty in the garden increases serotonin levels through contact with the soil bacterium Mycobacterium vaccae, according to University of Colorado Boulder researchers.

Walking barefoot in the mud, making mud pies, getting your hands dirty – it’s all good. No wonder I never want to wear my garden gloves. I have hand-scrubbing brushes by my hose and at every sink in my house.

Researchers in Australia claim that harvesting produce from your garden releases dopamine in the brain. They call it a type of addiction, in the best sense.

I wondered why I get so excited for the first strawberry, raspberry or blueberry of the season. I often take pictures to share with my family and on Instagram.

Serotonin and dopamine are both mood regulators, which is why mental health experts agree that nature’s therapy of planting, weeding and harvesting can help treat depression without medication.

Some researchers in Australia followed 2,805 men and women 60 or older over 16 years to try to identify risk factors for dementia in seniors. The study found a 36% lower risk of dementia among those who gardened daily.

There are many other health benefits to gardening. It promotes physical activity and provides exposure to sunlight, which lowers blood pressure and increases vitamin D levels, and of course, the fruit and vegetables that we grow are superior sources of nutrients.

Working in the garden can physically help with strength and balance. Gardening is an aerobic exercise that can easily use the same number of calories as working out in the gym.

Digging, raking, moving mulch, hauling watering cans, maneuvering wheelbarrows and mowing the lawn make for a good workout.

Using hand tools also keeps older hands strong and dexterous. Research shows that older adults who garden have better hand strength and pinching ability.

As with any physical activity, I have better success stretching before doing yard work. Also, I learned the importance of using the proper tools for the task and to take breaks as needed.

I wear my tools around my waist on a belt and have water handy so I can stay hydrated. I wear long sleeves or sunscreen if I am out for more than a half-hour.

We need the green

A single maple tree can remove 48 pounds of particulates and 100 pounds of carbon each year as well as toxic metals, nitrogen oxides and sulphur dioxide. I find that awfully impressive.

In densely populated neighborhoods, green space has become more important than ever. Increasing green vegetation in our environment “may mitigate the effects of climate change; in addition, evidence of an association between vegetation and lower mortality rates suggests it also might be used to improve health.” (Environmental Health Perspectives).

Living near green space might especially improve mental health and longevity for women. “Researchers from Harvard T.H. Chan School of Public Health and Brigham and Women’s Hospital compared risk of death with the amount of plant life and vegetation near the homes of more than 100,000 women … The data revealed that participants who lived in the greenest areas had a 12% lower death rate than women living in the least green areas.”

This brings us to the concept of “forest bathing,” or what the Japanese call Shinrin-Yoku. It does not mean bathtubs in the forest or running naked through the woods.

Researchers in Japan and China find “positive health benefits for the human physiological and psychological systems associated with the practice of Shinrin-Yoku … a traditional Japanese practice of immersing oneself in nature by mindfully using all five senses” (National Institutes of Health). 67% of Japan’s land mass is covered in forest, and forest bathing is extremely popular there.

Evergreen trees release airborne antimicrobial compounds called phytoncides (volatile oils) that protect them from bacteria, fungi, and insects. When we breathe in these phytoncides it’s been shown that they reduce blood pressure, heart rate and stress. (See Editor’s note below; terpenes are a subclass of phytoncides.)

One groundbreaking study even found that breathing in phytoncides increased NK cells (Natural Killer cells, a type of white blood cells) that fight viruses and cancer, and the effect lasted more than 30 days after exposure.

Several local gardens offer both guided and self-guided forest bathing tours. The Botanic Garden at UW has a map and links to gardens and is a good source for more information about the science. Close to Edmonds, Kruckeberg Botanic Garden hosts forest bathing, as well.

One of my sons is currently spending almost 100% of his time outdoors, backpacking on a trail in New Zealand called the Te Araroa, meaning “long path” in the native Māori language. It takes around four months to complete. He carries everything he needs including water and food. He goes into towns occasionally for supplies, but then he’s right back out on the trail.

He is more than halfway through his hike and well acclimated to walking over 20 miles a day. When I talk with him on the phone (when he has reception) he sounds very happy. I think his joy comes primarily from two things — the benefits of daily exercise and being surrounded by nature 24 hours a day.

As I grow older, I have time to reflect and live my life with intention. Growing up I spent a good deal of time outdoors; the kids in my generation played outside from the time we got home from school until dinner time and then until dark.

Recently I had a special opportunity to go to a forest bathing class with friends of North Creek. I wasn’t sure what to expect but it was a very visceral experience.

Spending time in nature, whether it is gardening, playing in the dirt, observing nature and green spaces or walking in forests is important.

People need to spend more time outdoors. We are lucky here in the Pacific Northwest to have so many beautiful outside settings to explore. I hope we will continue to scientifically research the health benefits of nature. I wish for you to be inspired and to do something special for yourself out there today.

— By Val Taylor

Val Taylor had her first garden when she was 11 years old. She grew up in the Skagit Valley and spent a lot of time working with fruits, vegetables and bulbs on local farms. After college, career and small kids, she attended the Master Gardening program in Seattle and volunteered for several years. She now belongs to five different Northwest gardening organizations. She is passionate about gardening and enjoys sharing.

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Editor’s note:
An ongoing study at UW’s Department of Environmental and Health Sciences is examining forest bathing. From Christopher Simpson, Ph.D., Professor of Exposure Science:

“There is increasing evidence from a number of studies that contact with nature, including forest bathing, provides benefits to human health including reduced stress, improved mood, reduction in cellular markers of inflammation, and increased resilience to buffer against the adverse health effects of everyday stress.

Specifically, we wanted to understand the role of olfaction (inhaling specific chemicals called terpenes from the forest air that we perceive as the smell of the forest) in the health benefits of nature contact.”

Volunteers wear powered air purifying respirators (PAPRs) that remove either air particles alone or particles plus terpenes, then are tested for mood, heart rate, blood pressure and markers of inflammation. Data collection is complete and is currently being analyzed.