The Nebraska Panhandle's semiarid climate and higher elevation makes it suited to a multitude of different crops, from sugarbeets to field peas to dry edible beans to proso millet to wheat to corn. However, one fragrant field off Highway 92 near Melbeta, Neb., is home to an entirely new crop: mint.
Husband and wife Dan and Becky Fitts of Melbeta are growing 30 acres of peppermint. While it's not a common crop in Nebraska, Dan notes it's grown in southern Idaho — where the climate and growing conditions aren't that different from the Panhandle.
"Another grower who grew up here and lived in Idaho for a while got into mint production, and moved back here and got me started," Dan Fitts says. "He grew mint for two years on a farm we leased to him. Then he moved back to Idaho for personal reasons. He let me know I could have that farm back. We ended up buying him out and taking over the mint acres."
Mint stands can last for five to seven years in Idaho, and Dan notes his friend, Vance Janicek, had grown the stands of spearmint and peppermint for two years before Fitts took over.
"Up in Idaho, they have to worry about more diseases," Becky says. "It's because of diseases like verticillium wilt that they have to keep under control that they have to rotate out of mint after so many years. We don't know for sure, but we hope the stand lasts longer here."
Mint stands are transplanted from "nuclear " roots — certified, disease-free roots from a nursery, which are grown for a year and then harvested to transplant for commercial production. Typically, an acre of nuclear roots will yield 10 acres of commercial production.
"Certified root is really expensive," Dan adds. It's about a $7,000-per-acre investment for new roots. "That's part of the reason we took it over from Vance. I'd hate to waste it."
Different production process
While they've grown both peppermint and spearmint for the past several years, this year the Fittses gave up their spearmint stand and are only growing peppermint. Spearmint is cut and swathed twice a year — in July and October, right when other crops are harvested. Peppermint is harvested in August, which fits the couple’s schedule better.
Dan notes both peppermint and spearmint are nitrogen-intensive, requiring as much as 300 to 350 pounds per acre annually. Most of it is applied early in the season in the form of dry urea.
"We spoon-feed nitrogen constantly and keep it in vegetative mode,” he says. “That keeps it from going to bloom. Once the mint blooms, your quality starts going down, but quantity starts going up. So, we spoon-feed nitrogen through the summer."
Mint also likes to stay wet, although the leaves are best kept dry to prevent fungal disease such as powdery mildew from spreading. So, the Fittses irrigate their mint field with flood irrigation.
"The oil is on the leaf,” Dan says. “So, if you're pivot-irrigating, you're washing some of the oil off. When it gets close to harvest, you don't want to keep it too wet.”
Peppermint grows to full height in midsummer before laying over. After this, new growth comes through, and when this second growth reaches full size and is about to flower, it's ready to harvest. That regrowth is where most of the oil is, and at this time, around mid-August, it's swathed — similar to alfalfa — before letting it cure for a day.
Once it's cured, it's chopped with a forage harvester and blown into enclosed, sealable wagons called mint tubs. Steam is pumped into the tubs through pipes to vaporize the oil. Steam is then collected through a hole in the top of the tub. A hose is mounted to the top, like a chimney, to recapture the steam before it is channeled into a homemade still on a semitrailer. The remaining product in the tubs, called "mint sludge," is similar to silage, and is spread back on the field later.
The steam, which is heated up by a boiler on the still, passes through a condenser, which catches it and cools it off and condenses it back to a liquid. Then, a separator is used to separate the oil from the water, the oil is skimmed off the top, siphoned out and put in a 55-gallon galvanized barrel.
Shooting for higher production
Mint oil doesn't spoil over time, especially in galvanized barrels. And with current lower volumes, Dan notes they can easily haul it in the back of a pickup to Labeemint, a processor in Nampa, Idaho, usually once a year.
"The toothpaste companies want every batch to taste the same. The same for gum companies," Becky explains. "Labeemint is the middle man that mixes the oil and does all the testing to meet the specifications required by end users."
From a production standpoint, one of the biggest risks in oil quality is the production of furans as a result of blooming early. "As the mint matures, it will flower more, and oil quantity goes up, but furan will also go up in the oil itself," Dan says. "That's where the nitrogen applications keep it in the vegetative state. That all goes toward getting low-furan oil."
Although an August harvest fits their schedule, another challenge is the potential for monsoon-like rains in late summer.
"That's the worst time to get rain,” Dan says. “A heavy rain will wash oil off the leaf, and it doesn’t have time to recuperate. Typically, we have hot and dry Augusts, however. We've done two full harvests. Both years we've had the monsoon issue right at harvest, and we've yielded around 85 pounds per acre both years. In Idaho, I understand 100 to 110 pounds is really a good yield, and that's what we're shooting for."
This is their third year growing mint, and after this year, they will have established a baseline for production history needed for federal crop insurance.
"To really make it work, we need more than 30 acres, but we're not going to expand until we have some insurance," Dan says. "I haven't made the decision yet, but once we're able to insure our mint production, our risk will be a lot lower, and expanding our acres is definitely an option."