When you think of vegetable production, do soil and open skies automatically come to mind? Well, think again.

Increasingly, greenhouses are being used to grow high-value vegetables and herbs for the commercial hydroponic industry. Growers are taking advantage of controlled environment agriculture (CEA) as leafy greens, tomatoes, basil and other produce are being grown indoors under conditions that can be monitored and optimized.

“We’ve been seeing double-digit annual growth in wholesale greenhouse vegetable production in New York over the last 10 years, the majority of that being hydroponic production,” said Neil Mattson, associate professor in the Horticulture Section of the School of Integrative Plant Science.

To better prepare Cornell students to thrive in this innovative industry segment, Mattson initiated a course this fall, Hydroponic Food Crop Production and Management, to teach the principles and practices of commercial food crop production in CEA.

“The course is the direct result of the industry telling us through our advisory board that they need agricultural leaders and a skilled workforce to continue expanding,” Mattson said.

Hydroponics is a method of growing plants in water instead of soil. To supply nutrients, a carefully formulated fertilizer solution is circulated to plant roots in containers, with the roots often supported by an inert substrate such as rock wool and a coconut husk fiber known as coir. Hydroponics is particularly well-suited for high-value crops such as herbs, microgreens and fresh vegetables, Mattson said.

The course features hands-on labs at the Kenneth Post Laboratory Greenhouses on campus, where the 13 students in this fall’s class split into teams to manage crops of tomatoes, cucumbers, greens and herbs.

In the lab sessions, students plant the crops, formulate and manage the nutrient solutions, trellis and prune plants, supply supplemental lighting, harvest the crops and record data on crop performance. They also scout for pests and release beneficial insects and other biocontrols as needed.

“Since we start each lab with a salad bar from our crops, the students have extra motivation to do their best as well as taste firsthand the benefits of fresh, local produce,” Mattson said.

The students weren’t the only ones to enjoy the bounty of their work: This fall, the class donated more than 1,000 pounds of surplus produce to Tompkins Community Action’s emergency food pantry in Ithaca.

“Our food pantry visitors were pleasantly surprised and grateful for the fresh produce grown at Cornell,” said Lee Dillon, Tompkins Community Action’s executive director. “Our ever growing partnership with Cornell horticulture under the supervision of Neil Mattson is simply fantastic, and helps us fulfill our mission of nourishing families here in Tompkins County.”

The students also conducted their own original experiments. One team analyzed the use of reprocessed cotton, wool and silk fabric scraps as crop substrates. Another team added citrus oil to their nutrient solution for basil to see if it affected the herb’s aroma. “In a blind test, I could totally tell which basil got the oil,” Mattson recalled. “But the oil hurt production, so the technique will need some fine-tuning.

“Our labs are not a substitute for real-world experience in a commercial operation,” Mattson said. “But we do take the students through the whole process, just on a smaller scale.”

A three-day field trip to visit greenhouse production facilities in the Northeast gave students a chance to see firsthand how the principles they learned in class are applied on a larger scale.

Mattson said the practical, hands-on experience of the course gives students a taste of what the industry needs as this agricultural sector continues to grow.

“After taking the course, several students told me that they now want to make this their career,” he said.

For more information on hydroponic growing, visit the Cornell Controlled Environment Agriculture website.

Craig Cramer is communications specialist in the School of Integrative Plant Science.