Honeybees explore a sunflower on the Vollmer-Sanders farm.
A PLUS FOR POLLINATORS - Honeybees explore a sunflower on the Vollmer-Sanders farm. ©: Paul Kingsbury/The Nature Conservancy

Food & Water Stories

Discovering the Soil Health Benefits of Sunflowers

How Sunflowers Enrich Soil Health and Communities

Carrie Vollmer-Sanders, North American Nutrient Strategy Manager

Nutrient Strategy Manager for North America Agriculture

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Have you ever done something and realized that your action had a consequence that you never intended? That happened to my parents, husband and me on our farm in Edon, Ohio. In the summer of 2017, we agreed to go in with two other farmers and grow sunflowers, to be planted after wheat harvest in July.

The sunflowers we grew have small black seeds and are sold for bird seed, not the large striped kind baseball players eat. We planted the first field, about 140 acres. We had problems with slugs eating the roots, and the crop looked pretty thin as it began to grow in August. However, by September, it was a beautiful field of four-foot-tall little sunshines staring back at us with unbelievable radiance. The sunflower fields were such a hit with local passersby that my mom set up an old milk can, pumpkins and a small picket fence to help the photographers know where to safely park.

We planted sunflowers to add revenue to our farm’s wheat acres. Having a second crop during a growing season can make the year more profitable, if the growing conditions are right. But we found the sunflowers brought other benefits when we added them to our crop rotation. Wheat keeps our soil covered through the winter, then we harvest it in the middle of the summer when there’s less farm work, and it breaks up our corn-soy rotation and adds more diversity of roots and microbes to the soil. When we bring sunflowers to the rotation, they do all of those same positive things, and they’re in the field from July to January (yes, we harvest it in the winter!), still allowing us to plant soybeans the next spring.

Carrie Vollmer-Sanders with husband Ryan at their sunflower field.
Sunflower Farmers Carrie Vollmer-Sanders with husband Ryan at their sunflower field. © Carrie Vollmer-Sanders/TNC

Soil Improvements in a Single Growing Season

All of us sunflower growers were eager to see what the soil would be like this past spring, our first planting following a sunflower crop. After planting into the harvested sunflower fields, our fellow farmers described their fields as “mellow,” not cloddy or hard, and easy to plant into. Mellow soil is like holding a homemade biscuit or shortcake. It is firm yet breaks into pieces when you rub it in your hands. Stressed soils are like the biscuits in a can; they do the job, but they are sticky, flaky, and can come off in layers not crumbles. Sunflower roots have a deep taproot breaking up some of those soil layers and bringing more different kinds of beneficial bacteria, fungi and microbes (“good bugs” as I refer to them) than our typical crops do. Because of this additional crop in our rotation, the soil is healthier and more alive with these good bugs.

While we were able to harvest our new “cover crop,” adding cover crops into a crop rotation typically means they are not harvested and are planted to keep soil in place through the fall and winter as well as provide other soil benefits. Cover crops are a new or different crop that is either flown on with an airplane dropping seeds over the field in August or September or planted with a planter after the main cash crop is harvested in October or November. According to the Natural Resources Conservation Service, cover crops reduce erosion, increase soil organic matter content, improve air and water movement through soil and reduce soil compaction. In as few as three years, organic matter—the stuff that holds water and nutrients—increases. Not long afterwards, farmers often find they have an increase in yield or profit as well when using cover crops. 

The Vollmer-Sanders farm with sunflowers in full bloom.
A BEAUTIFUL CROP - The Vollmer-Sanders farm with sunflowers in full bloom. © Paul Kingsbury/The Nature Conservancy

Enjoying Unforeseen Benefits

We initially tried sunflowers because we hoped for financial gain. We have not experienced that gain, but—and here’s the unintended consequence—we now have healthier soil and many happy neighbors. Although we planted them as a cash crop, the sunflowers functioned essentially as a cover crop for us, improving the soil as well as looking gorgeous for everyone in our corner of the world. I would venture to guess that the deer, birds, butterflies and bees are happier too, because they have an easily accessible and nutritious food source.

We may not plant sunflowers long-term because the market for them in our area is tricky. The sunflower seed buyer will only take a specific size and weight of sunflower seed, and whatever doesn’t make the grade doesn’t sell. I really hope we can figure out the financial piece to continue growing sunflowers long-term—sunflowers make our communities happier and our soil healthier. Those are the kind of unintended consequences I love! Regardless of how our sunflower market turns out, we will continue to plant cover crops as many farmers in our region do.

Have you thought about growing cover crops or adding a different crop to your current rotation? This goes for gardeners, too. If you are in the Midwest like me, check out mccc.msu.edu for information on the best cover crops to plant based on your field’s needs and the time to plant. Building your soil’s health is a journey. Some of the best practices are already known by farmers and scientists, and some practices may work better for you because of your specific situation—like sunflowers in northwest Ohio.  

Carrie Vollmer-Sanders, North American Nutrient Strategy Manager

Nutrient Strategy Manager for North America Agriculture

More About Carrie Vollmer-Sanders