5 Ways Home Gardeners Can Make More Robust Soil
As a child, Kristin Ohlson had easy access to gardens. Her grandparents maintained a small orchard and grew produce on their farm; her parents also planted huge plots of vegetables and flowers each year. While Ohlson didn’t develop a deeper agricultural interest until she grew up (all those hours harvesting vegetables cut into childhood playtime, after all), she eventually started researching how food is grown. And that research turned into a minor obsession.
In her 2014 book, The Soil Will Save Us, Ohlson documents how soil scientists are experimenting with cover crops, composting, no-till techniques, and other methods that help farmers reduce their reliance on fertilizer and rethink their relationships with soil. “Dirt First,” her more recent feature for Orion Magazine, and a Q&A with the Food & Environment Reporting Network (FERN) dive even deeper into the subject, exploring the role that microorganisms play in soil health, for both farm fields and backyard gardens.
“Plants pull carbon dioxide from the atmosphere through photosynthesis and create a carbon syrup,” she writes. “About 60 percent of this fuels the plant’s growth, with the remaining exuded through the roots to soil microorganisms, which trade mineral nutrients they’ve liberated from rocks, sand, silt, and clay—in other words, fertilizer—for their share of the carbon bounty.”
But before you chalk this all up as far too heady for the home gardener, check out her five easy steps for nurturing vegetables and flowers with natural methods based on that big-picture research—but applied to our own backyards.
1. DISTURB THE SOIL AS LITTLE AS POSSIBLE
Soil health starts with one basic principle: Don’t disturb the dirt. Sure, soil supports roots and helps hold up plants, but it also serves as a habitat for beneficial microorganisms.
“Underneath our feet is this incredible world teeming with billions of microorganisms that have been working in the soil for millions of years,” Ohlson says. “That ecosystem in the soil is what plants depend on for their nutrition, their water, and their defenses against chemicals, diseases, and insects.”
Rather than tilling garden rows and digging deep holes for new plants, she suggests leaving the soil structure as intact as possible. Poke small holes for seeds and dig slightly bigger spaces before planting seedlings.
2. MAKE PEACE WITH WEEDS
It may sound counter-intuitive—maybe even chaotic, in terms of landscaping—but weeds don’t need to be treated as an enemy. Even uninvited plants can help protect soil and feed the microorganisms at work below the surface.
“I used to dig up weeds or pull them out by the roots, but now I don’t want to disturb the soil. I go around with scissors and snip weeds off at the soil level instead,” says Ohlson. She then scatters clipped stems and leaves between the plants she wants to keep. This organic matter functions as mulch and acts as compost as it decomposes.
3. ENCOURAGE DIVERSITY
“In nature, there is this vast abundance of diversity—plants and insects and all kinds of life—in every square foot. This biodiversity helps feed and support the biodiversity in the soil,” she says. (Check out the incredible variety of plants in this enchanting Texas garden.)
Follow nature’s lead in your garden by growing a variety of vegetables, fruits, flowers, herbs, and other plants in close proximity. The variety promotes healthy, robust soil and might also attract a new mix of pollinators.
4. PLANT COVER CROPS
Every gardener has heard this one before, and Ohlson is a firm believer as well. She aims to keep her garden soil engaged, either by covering it in dead plant material or by nurturing live roots in the ground. Cover crops play a dual role. They interact with microorganisms by extending their roots as they grow, and they provide extra organic material to protect the soil once they’re harvested. In small gardens, simply clip cover crops with scissors and scatter over bare ground.
Not sure what kind of cover crop to plant? First, consider what might thrive in your location and climate. “Then, see what plants and flowers are native to your region,” Ohlson suggests. “But really, I think people can use almost anything, as long as it grows.” (These 5 cover crops will keep a small plot healthy.)
5. TRADE FERTILIZER FOR COMPOST
When plants rely on fertilizer, they get lazy. Their partnership with microorganisms in the soil changes, and that can impact the wider microbe community. By using compost instead, you’re enhancing the soil with a concentration of microorganisms and carbon that help plants thrive.
If making your own seems too messy or daunting, look into local sources. Some cities collect food waste and make the resulting compost available to the public. Elsewhere, garden and hardware stores sell organic compost by the bag. You might find regional farmers who can supply the materials you need, as well.
“I also put sticks, some food waste, and dead plant matter around my living plants. That keeps the benefits of compost happening on the most basic level,” Ohlson says.
FOR SMALL-SPACE GARDENERS
Ohlson’s overall advice is similar for gardeners who grow plants in pots or containers, where soil mindfulness is especially important.
“When water hits bare soil, it compacts that soil. Even the force of one raindrop can make an impact. So, the less that bare soil is exposed to water, the healthier that soil is,” she says. “Even in a small pot, I don’t want to be pouring water directly on the soil. I’d rather have it seeping through clipped plant material and reaching the soil in a gentler way.”
Ohlson has two raised beds in her own backyard and she packs them with a diverse selection of vegetables, flowers, and shrubs. “I plant things really close together and try to have a lot of live roots in the ground. It’s so rewarding to see the incredible production I get out of these two tiny raised beds,” she says.