What’s round and red and grows at the South Pole? A tomato!

It’s true. At the very bottom of the world, scientists working at the United States South Pole Station manage a greenhouse that grows fresh vegetables. It also provides a warm, bright place to relax during the long, dark winters. And it tests new technology that may one day help humans garden on the moon.

The station lies on top of the massive Antarctic ice sheet, which is up to two miles thick and thousands of miles wide. Outdoor temperatures at the South Pole can drop to 100 degrees below zero, and the sun does not shine for six months out of the year: not ideal conditions for growing vegetables.

But inside the greenhouse — known as the South Pole Food Growth Chamber — cantaloupe, peppers, cucumbers, tomatoes, herbs, leafy green vegetables such as kale and lettuce, sunflowers, other edible flowers and even watermelons flourish. About 13 pounds of plant material — roots and stems as well as fruit — are produced each day. The plants rely on artificial light and are grown in a hydroponic solution of water and nutrients, rather than soil. The approximately 37 gallons of water used per day come from melting ice from the ice sheet.

“There’s a lot going on inside the chamber,” said Lane Patterson, a University of Arizona scientist who manages the greenhouse.

The vegetables grown there are the only fresh food available to the 50 scientists and staff members who live inside the station from mid-February to mid-October, during the United States Antarctic Program’s winter season. During this time, there are no flights into or out of the station because of severe conditions. So the crew’s meals are prepared using frozen food flown in earlier in the year, and a fresh salad from the greenhouse is served every few days.

The crunchy, fresh vegetables aren’t the only benefit of the greenhouse, which is about the size of your classroom at school. The South Pole is cold, dry and dark during winter. But inside the chamber, “it’s bright, it’s humid, it’s green, there are great smells,” said Patterson. Staff members visit the greenhouse foyer after work to relax on the couch, eat dinner or take a break from the station’s persistent dry air.

Patterson refers to the greenhouse as a big “growbot,” a robot that grows things. He controls the conditions inside — such as temperature, light and the hydroponic solution — from his office in Tucson, with the help of a technician at the South Pole. “Through a computer and camera, I’m able to access the chamber and assist with questions that the operator might have,” he said. He visits the South Pole every few years to check on and maintain the greenhouse.

The greenhouse is a project of the University of Arizona’s Controlled Environment Agriculture Center. Its researchers are learning what it takes to grow food, refresh the air and cycle water through a growth chamber, all in a remote location with a small crew in a dangerous environment.

What they find may one day be applied to feeding astronauts. Using the South Pole greenhouse as a model, the center has also created a lunar greenhouse to test how to support life on the moon or Mars. For now, the people at the South Pole will gladly enjoy their tomatoes right here on Earth.

— Ann Posegate