(HOST) As gardening season really gets under way, it’s probably no surprise that commentator Charlie Nardozzi has been thinking a lot about soil. And he says that good soil is much more than just dirt.
(NARDOZZI) Any gardener knows soil is the heart and soul of a healthy garden. Two recent research articles demonstrate the complexity of soil. One article proves that soil does more for us than just grow our food and flowers, it can actually keep us happy. The other raises a concern about one of our well-known soil-dwelling critters, the earthworm.
First, the good news. Any gardener, and kid, knows playing in the dirt is good for your spirits. Well, it turns out this isn’t just a psychological phenomena; it’s a biochemical one, too. Researchers at the Bristol University and the University College in London found that naturally occurring, soil-borne “friendly” bacteria may affect the brain in a similar way as antidepressant drugs.
Doctors gave cancer patients medication containing common soil bacteria, Mycobacteria vaccae. They found patients had increased vitality and cognitive function and a decrease in pain after the treatments. It seems these mycobacteria stimulate the production of serotonin levels in the brain. Serotonin is that “feel good” chemical that’s linked to alleviating disorders such as anxiety, depression and obsessive-compulsive disorder. You don’t have to eat the soil to get a dose of mycobacteria. Just working your hands in it should be enough.
While gardeners working in the soil is a good thing, believe it or not, earthworms working the soil can be a problem. Most gardeners have been taught that earthworms are good for the soil. Their tunnels make water, air and nutrients more available to plants and help roots expand. However, few people realize that earthworms are an exotic species in New England and other northern states. These European natives originally arrived via the Colonists in ship ballasts and with plants.
While earthworms are great at tilling up the soil in our vegetable and flower garden, in the forest they can be destructive. Earthworms love to eat organic matter. In the forest they rapidly decompose the spongy organic matter layer on the forest floor. This layer is essential to the growth of tree seedlings, wildflowers, ferns and other fauna. It seems earthworms are decomposing the spongy layer faster than nature can replace it. While the native plant seedlings struggle to survive, invasive species move in. So, yes, even earthworms can be bad for the environment.
So, what’s a gardener to do? The main vehicle for earthworm’s spread is humans. The University of Minnesota has created some advice to help us stop the spread of earthworms into forest soils. If you’re using earthworms as fishing bait, don’t throw unused worms in the water or on land. Don’t transport leaves, mulch, compost and soil from one area to a forested area. If you compost using worms, let the compost freeze for one month to kill the earthworms and eggs before you use it.
It seems nature is never a simple black and white equation, and each action we do must be considered for all the consequences- intended or not.
Charlie Nardozzi is an all-around gardening expert with a special fondness for tomatoes and roses.