Inside Natural Grocers' Hydroponic Produce Container

Catherine Douglas Moran

July 7, 2021

Eighty-two steps away from the produce aisle of Natural Grocers store in Lakewood, Colorado, sits a shipping container filled with hydroponic produce. 

Inside, more than 4,000 heads of organic lettuce are grown every month across roughly 320 square feet — just a fraction of the roughly 1 acre worth of land it would take to conventionally grow the same amount, said Michael Boardman, manager of the grow unit, which the grocer calls GardenBox.

"Within this small space, there's a lot of possibilities," Boardman said while giving a recent FaceTime tour of the shipping container.

The GardenBox pilot marks Natural Grocers' first foray into organic hydroponic farming and furthers its commitment to sell 100% organic produce and invest in hyper-local production. Starting Wednesday, July 7, customers can buy the lettuce at the store for $1.99 per head.   

GardenBox grows seven to eight varieties of lettuce, including Hampton, Brentwood, Alkindus, Tropicana, Muir, Marciano and Truchas. Unlike seasonal greens, the lettuce in GardenBox can be grown year-round, meaning it's always in season.

"We're seeing consistency in the product, whether it's snowing 2 feet outside or it's 90 degrees outside," Boardman said. "The box does a really good job of regulating this temperature."

Courtesy of Natural Grocers

From seed to salad

A portion of the container is dedicated to seedlings and can hold 2,400 plants at a time, with roughly 700 to 800 organic seeds planted each week in organic-friendly peat and coconut husk.

Around the three-week mark, the plants get transferred to the three vertical grow walls. The walls are double-sided and on rollers so that the plants can get spread out for equal access to LED lights that mimic sunlight, Boardman said. After about eight weeks after the seeds are planted, most varieties of the lettuce are ready for harvest. 

The feeding, nutrients and water are automated through a computer system inside the box. The system also measures air temperature, humidity, vapor pressure deficit and pH levels. If any issues arise, the system sends Boardman an email. "The computer and box kind of run itself," Boardman said. "It's just us troubleshooting and then coming in planting and harvesting."

Lasting lettuce

The GardenBox lettuce, which is certified organic by Where Food Comes From Organic and has the Clean Hydroponic Produce seal, is sold with roots intact, which Boardman said lengthens its shelf life and provides a better flavor and more nutrients. 

"They taste amazing," Boardman said. "The taste is a really big selling point for me. You get a much stronger flavor out of all of them."

Courtesy of Natural Grocers

In some cases, the lettuce may get sweeter when the roots are kept in the water following the harvest. Fresh living greens also provide a more nutrient-dense product than traditional lettuces that have been shipped to the store, Boardman noted.

After getting harvested, the produce is sold loose on a spinning display with water in the middle of the store's produce department. Shoppers can then bag it with plant-based produce bags. 

Growing more greens

The idea for the hydroponic farm came from the Isely family, which started Natural Grocers in 1955, said Boardman, who joined the project in October.

The trickiest part of the operation has been figuring out the nutrients formula, which includes magnesium, cobalt, copper, manganese, zinc and iron, along with the organic growing process. "It took us several months to really dial in the organic nutrients. There's not a lot of organic hydroponic growers out there," Boardman said. 

Courtesy of Natural Grocers

The first harvest happened in June, though Boardman said experimentation is continuing with different types of lettuce. Not all lettuce is prime for hydroponic farming, but the varieties in the box now, including butter lettuce, red romaine, and green and red oak leaf, are doing well, Boardman said. "I love [the oak leaf lettuce]. It comes out beautiful ... It just really thrives in the box," Boardman said. 

Typically, hydroponic farming produces crops faster and saves more water than traditional farming. As part of the Clean Hydroponic Produce Standards certification, the grocer will be participating in scientific research studies on nutrient density and energy use.

GardenBox plans to eventually grow herbs for Natural Grocers, though for now, the focus is on perfecting its leafy greens, Boardman said.

Natural Grocers aims to bring GardenBox containers to more stores. "Right now, we've got one more store that we're planning on opening up with a box shortly within the next few months. But beyond that, I'm still not sure what the steps will be," Boardman said. 

Lead Photo: The grocer's first foray in the futuristic farming technology, GardenBox, grows 4,000 lettuce heads per month and sits just steps away from a Colorado store's produce department.