Discover more from The Weekly Dirt with Jessica Damiano
How to divide a sedum, and the health benefits of gardening -- with scientific evidence
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A few years back, I wrote an article about cancer survivors who turned to gardening after their diagnosis to decompress and find some peace amidst the turmoil.
Something about digging in the dirt and communing with nature seems to lower stress and impart a sense of well-being, whether we’re sick or not. I know that planting, weeding, harvesting and otherwise tending to plants certainly distract me from everyday problems.
I’ve always believed in a mind-body connection, as stress can literally alter our physical health — high blood pressure, stomach ulcers, heart attacks and other ailments, some life-threatening, have been linked to stress. So, to me, at least, it stands to reason that activities like gardening that lower stress hold the potential to improve our health.
And now, the results of a study released by researchers at the University of Colorado-Boulder back this up scientifically. They found that community gardening, in particular, provides multiple tangible health benefits ranging from improved mental health to reduced cancer risk.
The study, conducted between 2017 and 2019, was the first-ever controlled, randomized trial to examine the health of community gardeners. Researchers recruited 291 people who had not gardened for at least two years but were on waiting lists for community plots in Denver and Aurora, Colorado.
Half the participants were randomly assigned to remain on the waiting list and refrain from gardening for the year. The other half were provided with a free gardening plot, a beginner’s gardening class, seeds and starter plants.
By the end of the season, the gardening cohorts reported a 42-minute weekly increase in physical activity, lower stress and anxiety levels, stronger social connections and a roughly 7% increase in daily fiber intake. All those factors have been shown to modify risk factors for mental and physical illnesses, including type 2 diabetes, high blood pressure and cancer.
Although not controlled and randomized, previous studies have reported similar findings among home gardeners. In 2020, researchers from the University of Exeter and the Royal Horticultural Society in the UK found the health and well-being benefits of gardeners over non-gardeners were similar to those found among people living in wealthy areas over those in poorer ones.
And a 2019 study conducted by Texas Sprouts, a research grant sponsored by the National Institute of Health that supports school gardens and nutrition and cooking programs in Austin, Texas, found similar benefits among children. Students who participated in the program increased their vegetable intake by 20%, had improved blood glucose control and decreased cholesterol levels. Academically, they showed a 12% increase in focus on their lessons and improved standardized test scores.
In 2007, Mycobacterium vaccae, a naturally occurring beneficial soil bacteria, was found by researchers at the University of Bristol (UK) to increase serotonin levels in mice. A few years later, I wrote about a similar 2013 study by the National Center for Biotechnology Information in Bethesda, Maryland, that found that exposed mice demonstrated “a reduction in anxiety-related behaviors” and had a two-fold increase in speed when completing a maze.
Simply spending time in nature, whether forest bathing, hiking or sitting in a garden, has also been shown to be beneficial. In 2015, Stanford University researchers compared the brain activity of people who spent 90 minutes walking in a natural environment with those who walked for the same amount of time in a high-traffic urban setting. The nature-exposed group demonstrated decreased activity in a part of the brain associated with depression.
But none of this is news to us! Gardeners have known for eons that being among plants, hearing bees buzz and birds chirp, and experiencing the miracle of a seed sprouting into a plant provides an unrivaled sense of joy and peace. The only thing that’s changed is that science has finally caught up.
📬 Ask Jessica
DEAR JESSICA: I am a desert gardener in New Mexico. After decades in Wyoming, where I nurtured native plants for a federal land management agency, I acquired this tall and leggy sedum with my house purchase.
It gets 6-8 hours of full, retina-frying sunshine every day and has been totally dependent upon sky water, though I gave it a drink on July 15. The pot is broken, and its soil is as hard as granite.
The cacti, Japanese honeysuckle, barometer bush, salvia and four-winged saltbush in the xeriscaped yard are doing well, but this poor slob by the porch leaves my ❤️ as broken as the pot.
What can I do about my sad sedum? —Eva Warren, Socorro, NM
DEAR EVA: Too much water and insufficient sunlight both can result in leggy sedums, but you’ve indicated neither is to blame, so we can rule those out as culprits.
However, you didn’t mention if the plant has been fertilized, at least on your watch. Too much nitrogen can force tall, leggy growth, so when fertilizing, opt for a slow-release product instead of a fast-release one.
In addition, many plants — including sedums — form a dead hole or gap in their centers when overgrown and need dividing.
The first thing I would do — immediately — is prune, divide and repot the plant. This ordinarily would be best done in early spring, but since the container is broken and the soil is hard, don’t delay. Hard, dry soil — much like a hard, dry kitchen sponge — will not absorb water easily.
First, prune each stem down to about six inches tall, cutting each on the diagonal just above a leaf. (If you plant each top portion in another pot or in the ground, you’ll get free plants!)
Select a pot(s) with a drainage hole in its bottom that is only 10% deeper and no more than 2” wider than the plant’s root system. Fill it (or them) with two parts horticultural sand, two parts ordinary potting mix and one part perlite. You can purchase a commercially blended mix specially formulated for cacti if you prefer.
Remove the plant from its pot and carefully remove soil clinging to its roots. Examine the junctures where the roots meet the top growth to determine the best division points.
Using a sharp knife, cut the roots into 2-4 sections, ensuring each has several stems attached, then situate each into its new home. Add more potting mix around their bases, pressing firmly to remove air pockets. Take care not to bury (or leave exposed) any part of the roots.
Immediately after repotting, water well and keep the plants consistently lightly moist in a partly shady spot for about two weeks while they recover, then gradually move them into more sunlight. Don’t fertilize until spring.
💡 If you do one thing this week…
Work bone meal into the soil around fruit trees, flowering plants and planted bulbs (you can also add to planting holes when adding new bulbs in autumn).
The organic amendment, made of powdered animal bones, is high in calcium and phosphorus, which boosts fruiting and blooming.
Just a few notes:
Follow the dosing instructions on the package — you know what they say about too much of a good thing.
Test your soil pH and apply bone meal only if the reading is below 7.0. The product is ineffective in alkaline soils (those with a pH reading of 7.0 or higher).
Because bone meal is comprised mainly of bloom-enhancing phosphorus, your plants will still need nitrogen and potassium, so continue to apply your regular fertilizer, as usual.
👏 Sunday shoutout
Hey, Jessica! Here are some beauties from my garden. I also wanted to tell you I tried your trick of rinsing my blueberries and raspberries with vinegar, and it really does work! Thank you much for sharing that. —Kate Baker, Locust Valley
Hey, Kate! I love the color variations of your hydrangea flowers (caused by uneven soil pH levels around the plant), and I’m glad you’re enjoying my berry hack!
Send in your photo, and you could be featured next (bonus points if you’re in the picture!)
📰This week in my Associated Press gardening column
I write a weekly gardening column for the AP, so you might have seen my byline in your local paper (or news website) — wherever in the world you happen to be. In case you miss it, I’ll post the most recent here every week.
This week: Deer, rabbits and voles — oh, my! Tips for determining what’s eating your garden — and what to do about it.
Before that: Tips for dealing with flooded plants
One week prior: Are ants in your plants harmful?
You can read all my AP gardening columns here.
📚📺🎵 Random things I enjoyed this week
📺On the recommendation of a friend, I watched a documentary series called “Bad Vegan” on Netflix. I liked it. And that’s where my problems began.
Netflix took my “like” and ran with it, not only recommending I watch more documentaries, which I almost never do, but hijacking the top five “Recommended for Jessica” categories on my homepage.
Suddenly, I was faced with choices that included documentaries, docu-series, true-crime documentaries, crime documentaries and just plain true crime instead of the usual irreverent comedies, sci-fi thrillers, and post-apocalyptic, dystopian-future content I’d become accustomed to. I didn’t realize a decade’s worth of algorithm-building could unravel so quickly.
The good news is that it only took a few deliberate viewings to restore order. Within a couple of days, I was back in business, watching the German movie “Paradise,” about a future when people can buy and sell years of their lives to each other, sometimes unwillingly — which, by the way, I highly recommend (the movie, not the practice 😉).
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I welcome your comments and suggestions, so please send them along — as well as any topics you’d like to see covered and questions you’d like answered in the Ask Jessica section.