The Hippo


Apr 22, 2019








Lettuce plants thrive on a hydroponic growing system. Courtesy photo.

Keep the greens coming
Investigating hydroponics for fresh winter produce


It takes Robert Demers about five minutes to walk from the front desk of Demers Garden Center in Manchester to the greenhouse where he grows produce. The greens customers buy at his store are probably about an hour old. 

Compare that to most out-of-season produce available at grocery stores: It’s picked by a farmer, put on a truck, shipped to the airport and then transported to a store. 
“And who knows how long it sits around. It just amazes me,” Demers said. “You’re looking at diesel fuel, jet fuel, and it’s just pollution.” 
In the summer and early autumn months, getting fresh local produce is a breeze, but more and more New Hampshire farmers are looking to fulfill a demand for local veggies throughout the winter too. 
The interest has inspired researchers at the New Hampshire Agricultural Experiment Station at the University of New Hampshire College of Life Sciences and Agriculture to launch an investigative hydroponics project. 
“There’s been a lot of interest in the greenhouse industry to be growing greenhouse veggies, particularly salad greens, in hydroponics,” said researcher Brian Krug, “Most New Hampshire greenhouses are only used seasonally, primarily in spring. They’re looking for different ways to produce revenue specifically with winter farmers markets taking off in the last few years.”
Hydroponics is a method of growing plants in mineral-infused water instead of soil. UNH has been expanding its research on the process, and this spring Krug installed hydroponic units at the New Hampshire Agricultural Experiment Station Macfarlane Greenhouses, where he conducted preliminary feasibility tests. Recently launched projects will look at how growers can transition into hydroponics seasonally and switch their greenhouses back and forth. 
“We’ll look at nutritional requirements, fertilizer, light and heating requirements, how long it takes to get a mature crop, expected yield, and different types of hydroponic production,” Krug said. 
In the beginning, the researchers will work with specialty greens. 
Krug has been working with local growers who already transform their greenhouses for hydroponics in the winter to understand the questions and problems they are experiencing. One of those farmers is Demers. He has been converting his greenhouse’s ebb and flow benches into a hydroponic system for two years. It’s a complex system with a steep learning curve, he said. 
“I’m putting in a new computer to better regulate the heat, but I found it’s very important to always have air movement in hot days, and we also need to come up with some kind of lighting system. In the winter, you don’t have enough daylight to yield crops quickly. You have to turn the crop over… you’ve got to produce a crop that will pay for the energy.”
Demers hopes the UNH researchers will help growers find the most efficient energy sources; battling high energy costs is a concern. 
Demers has also identified some of the problems with growing various kinds of greens. One grew so well that the roots got so large they were hard to pull out of the styrofoam that holds them down. Another developed brown spotting because they were left touching the water too long. 
Krug began his first experiments in September, and they will be ongoing for as long as it takes to answer the important questions about lighting and which crops will grow the best. 
“As long as growers have questions, we’ll continue to do research for the foreseeable future,” he said.  
As seen in the October 2, 2014 issue of the Hippo.

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