By Shelby Whitaker

As you reach for a candy cane this holiday season, remember that the Hoosier State ranks third and fourth in the U.S., respectively, for spearmint and peppermint production, according to the Indiana State Department of Agriculture.

Randy Matthys is the fourth-generation owner of Shady Lane Farms in South Bend, Ind., one of the oldest growers of peppermint, spearmint and scotch mint in Indiana.

“There’s 230 acres here on the home farm, and my grandparents started farming here in 1932,” Matthys says. “It’s been rewarding, and it’s been as challenging as anything.” He grows mint on 5 of those acres.

The growing process

Mint is typically planted in the spring, soon after the ground has thawed. It is planted by stolons that are cut into 4-inch pieces. These mint stolons are horizontal stems that grow from the base of the plant just above the soil surface and produce new plants from buds at their tips.

Once established, mint is a perennial. This means it will regrow each year, with harvest beginning in late summer depending on the plant variety and weather conditions.

“It kind of follows the 41st to 42nd parallel across the country,” Matthys says. “I’ve always been told the plant must go into dormancy to produce oil the next year. It needs to have that season.”

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The crop requires well-drained, fertile soil and benefits from a moist environment. It has a shallow root system that is sensitive to drought. Irrigation systems often are used to maintain ideal growing conditions.

Petrus Langenhoven, a Purdue University Extension vegetable specialist, says northwestern Indiana’s soil and climate is ideal for increasing mint production.

“For instance, we can grow mint here in West Lafayette, but the mint oil yield will be a lot lower than what it will be in the northern part of the state,” Langenhoven says.

LOTS OF VOLUME: “You handle a lot of volume of mint hay to get a small volume of oil,” Matthys says. Here, he opens a mint hay wagon.

Harvesting mint hay

Mint growers mow the crop in August through October, cutting and swathing with no crimping. They then leave it to dry in the field for about two days. The hay is then chopped and blown into large wagons or tubs to dry. Matthys says his tubs will hold anywhere from 16,000 to 20,000 pounds of mint hay. This is about 60 to 120 pounds of oil per tub once it is distilled.

Earlier harvests on certain varieties also can allow for mint to have a double cutting if conditions are ideal and if plant regrowth reaches a certain height usually 60 to 65 days after the first cut. The oil quality does not decrease with a second cutting.

“The quality of the oil will remain the same, but the quantity will be a lot less,” Langenhoven says. “They just try to maximize how much oil they get from that acre for that year.”

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As with alfalfa hay, leaves are an important component of mint hay. Fewer leaves equal less mint oil.

“A lot of people don’t realize how much effort goes into collecting leaves,” Langenhoven says. “The main oil content is in the leaves, so if the grower loses leaves due to rain or a delay in drying, it can result in significant financial loss.”

Once the wagon is full of chopped mint hay, the mint is then put through a hydrodistillation process. The wagons are hooked up to pressurized steam directed through small openings in the floor of the wagon. Both steam and mint oil are condensed and separated into a tank. Due to the density differences, mint oil rises to the top, and water sinks to the bottom.

Once separated, mint oil is skimmed from the top. Extracted mint oil is stored in stainless-steel barrels, weighed and sold to distributors.

“The oil is our crop, " Matthys says. “That’s what we’re after.”

A PURE PRODUCT: Shady Lane Farms’ mint still is made from stainless steel and inspired by a company in Oregon. To keep the oil pure between varieties, it is essential to flush out the system from any impurities such as carvone or menthol, which differ between the plant types.

Matthys says the process has never changed, even as technology and equipment have evolved.

“The equipment has changed, but the process is what I remember from years and years ago,” he says.

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Beyond the growers

Once sold, the essential oil is used in a variety of products throughout the U.S. and internationally, including toothpaste, candy and lotions. 

“Colgate and Mars Wrigley are big supporters of the American mint industry, which includes the Midwest here in Indiana, Michigan and Wisconsin,” Matthys says.

Matthys enjoys attending the Midwest Mint Growers Conference hosted by the Indiana Mint Market Research and Development Council to network with other growers and industry personnel.

“You get to meet all the people from different facets, all the areas of the production and the end users, and the handlers and the dealers in between,” Matthys says. “You know a lot of great people in the industry.”

In these meetings, industry leaders often discuss topics of collaboration and concern. One constant challenge for the mint industry is the soil-borne disease Verticillium wilt, which poses significant risks to peppermint and scotch spearmint crops in some of the country’s older growing regions. Yet, the future is forward-looking. Many work to create a Verticillium-resistant crop and continue to grow and expand technological advancements.

A REMINDER: A photo of the farm’s original mint still from the 1930s is kept on display. The current still was built in 2016.

The dedication of Indiana’s farmers and researchers reflects the skill required to produce mint successfully. Because of their efforts, Indiana’s mint fields bring both flavor and economic value to the state’s agricultural industry.

“The people you meet that use our product, and those that do use the natural mint-flavoring toothpaste, chewing gum or whatever, maybe we helped flavor that,” Matthys says.

Head to Purdue’s mint oil production webpage for additional information, guides and research on Indiana mint production.

Mint production steadily declining

Indiana has always been a major player in the mint industry. Mint oil in the Hoosier State is often regarded as high quality, Langenhoven says. However, growing the crop doesn’t come without its challenges. Growing the crop includes physical and external challenges that have negatively affected many growers.

“We’ve lost growers here in the Midwest that could probably still be growing mint if we had the demand for the oil that we once had,” Matthys says. “Now, it keeps slipping away because of foreign oil, synthetic production and too many flavorings to choose from in toothpaste.”

Yet, the decline of Indiana mint production isn’t just a story of shifting consumer preferences — it’s a battle on disease threats and market pressure.

“Verticillium wilt is probably our biggest enemy on the peppermint side,” Langenhoven says. “And that has reduced acres, together with market pressure. A lot of companies in the U.S. now buy oils from locations that produce it much cheaper.”

Verticillium wilt is a soil-borne disease caused by a fungus that poses significant risks to peppermint and scotch spearmint crops. Once the fungus contaminates a field, the plants yellow and wilt, and their ability to compete with weeds is reduced, eventually leading to the death of the mint plant.

“When I started at Purdue nine years ago, I think we had about 14,000 to 15,000 acres of mint,” Langenhoven says. “This season, it’s around 4,000 to 4,500 acres, so drastic decrease, and it’s really the old guys that are hanging onto the industry — they still want to make some impact.”

QUALITY CONTROL: Matthys extracts a small amount of mint oil to showcase the product. Shady Lane Farms’ mint oil is stored in large barrels before being sold to suppliers by weight.

The Indiana Mint Market Development and Research Council conducted a study before the pandemic that looked at consumer thoughts on mint and organic mint. The results concluded that it didn’t seem consumers really cared about the origin of mint flavoring.

“There is a very small amount of mint oil in gum and toothpaste,” Langenhoven says. “And, therefore, the consumers don’t really think about where it comes from and the impact it has on growers in the U.S.”

Checking labels for natural mint ingredients is a simple way to support Indiana farmers and preserve the tradition of quality mint production.

Whitaker is a senior in agricultural communication at Purdue.