A group of Penn State students huddles over a wooden worktable in Headhouse II. Their hands move in unison as they clip the leaves and clean a harvest of microgreens, which were planted in the greenhouse in early spring. In a few days, the gardeners-in-training will dine on the tiny leaves (that look more like shamrocks than lettuce) during an end-of-semester potluck.
Alongside their microgreens, the students grew organic tomatoes, cucumbers, eggplants, peppers and herbs as part of a hydroponics and aquaponics class, which taught the ins-and-outs of using soilless processes to grow plants. The students’ efforts — which on a weekly basis yielded up to 80 pounds of cucumbers alone — were a success, in part, due to new technology added to the nearly 60-year-old greenhouse.
Headhouse II, which was built in 1960, and eight other College of Agricultural Sciences greenhouses were updated last year with climate-control computer systems, LED lighting, a rooftop weather station and other automated tools.
Like plants in any ecosystem, those in greenhouses need a well-calibrated mixture of light, water, air and nutrients to thrive. However, creating ideal climate conditions and growing habitats can be expensive in older buildings, according to Scott DiLoreto, greenhouse operations manager at Penn State. He said adding the modern climate-control technology has helped him to not only grow healthy plants, but to reduce energy costs and outputs as well.
“The technology we added has made it possible for teaching, learning and research to happen in the greenhouses at a scale that wasn’t possible before,” DiLoreto said. “Prior to the upgrades, a number of the greenhouses weren’t particularly useful in summer or winter, because temperatures would be too high or low to grow plants. Now that we can efficiently control the internal climate, there’s more usable space and it’s more functional for a range of activities.”
Using a new Wadsworth climate-control system, DiLoreto is able to manage the mechanical systems (including air circulation fans, misters and heat pumps) that determine temperature, light and humidity in every compartment of each greenhouse — about 50,000 total square feet. While he can pre-program or change each setting manually from his computer or smartphone, he can also set the system to auto-adjust based on outside weather conditions.
“We installed a rooftop weather station on Headhouse I that measures wind speed, wind direction, temperature and light intensity from the sun,” DiLoreto said. “The information from the weather station communicates with each greenhouse compartment computer, so I can program the mechanical systems to automatically adjust based on the weather outside.”
When sunlight goes above or below a pre-programmed value, new supplemental LED lighting, which replaced the older high-intensity discharge lights, will kick on or off.
“If the sun gets really bright, you don’t need the LED lights,” DiLoreto said. “Conversely, I can program it so that if the lights are off in the greenhouse and it all of a sudden gets really cloudy outside, the weather station will detect that and tell the computer to turn on the lights. And since LEDs only produce the red and blue wavelengths that drive photosynthesis, no energy is wasted producing light that doesn’t support growth.”