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Students work to improve agriculture program results
Brian Roach, lab technician at Patrick Henry Community College’s Agriculture Research Center (ARC), checks on the progress of plants being grown under two- by eight-foot LED panels assembled by Roach and designed by PHCC’s Assistant Professor of Viticulture/Enology and Horticulture John Ayers. (Bulletin photo by Ashley Jackson)
Monday, September 17, 2012
By ASHLEY JACKSON - Bulletin Staff Writer
Patrick Henry Community College’s Agriculture Research Center (ARC) still is in the experimental stage of its efforts to find the best ways to grow plants without sunlight.
Last semester was the first test for the project that has a goal of using vacant buildings in uptown Martinsville for something that could benefit the community and possibly create jobs in the future by growing marketable crops of lettuce and other salad greens, according to Brian Roach, lab technician at the ARC.
Its first semester produced a 90 percent crop yield, and horticulture, agribusiness and viticulture students at PHCC were able to take many plants home to eat, he said. The hope is to sell the vegetation to the public some day, but he is unsure whether that will happen this semester because it found that packaging was expensive last semester, Roach said.
“We’re just going to keep experimenting and find out what grows best under which light,” he said. “Time will tell what works the best.”
Despite the crop yield, there were challenges in its infancy.
For instance, fluorescent tube lights were used at the ARC building at 133 E. Main St., which did not allow the plants to “mature enough to be productive” because there was not enough light range to grow, Roach said.
Plants require an active range of 400 to 700 nanometers of light to grow, which the fluorescent lights didn’t provide, he said.
Another issue was that the fluorescent lights were mounted above the eight vertical hydroponic (water) units. Not all of the plants received enough light, so only those near the top of the vertical units matured, he added.
This semester, the center is not using any fluorescent lights or vertical hydroponic units. Instead, the hope is to install LED (light emitting diode) lighting with the vertical hydroponic system next school year, Roach said.
The other light sources used last semester were round LED light fixtures and square LED panels. Both were successful at maturing the plants, especially the round LED fixtures. However, the round fixtures were expensive and the center chose not to use them again this semester, he said.
The goal of the center is to yield a crop with the least expense, he added.
To experiment with more LED lights and keep costs down, the center chose to use the 12-inch square LED panels again this semester along with new four-foot tube LED lights and two- by eight-foot LED panels assembled by Roach and designed by John Ayers, PHCC’s assistant professor of viticulture/enology and horticulture, Roach said.
Since planting two weeks ago, the new lighting has shown to be efficient and plants are growing, with the tube lights showing the least efficiency, he added.
Changes also were made this semester in the varieties of plants being grown.
There are four varieties of lettuce now growing in the ARC, along with one variety each of kale, spinach, basil and turnip greens, Roach said. Harvest is expected around mid-October.
Five varieties of lettuce, including semi-head lettuce and cilantro were grown last semester, he added.
Roach said the center is only growing leaf lettuces this semester because while the semi-head lettuce grew last semester, it did not yield large heads of lettuce. He feels that may have been caused by insufficient air circulation in the building to keep fungus, mold and disease down, or there wasn’t enough room for the heads to grow in the four-inch-wide plant beds, he added.
The lettuce simply grew “to its environment,” Roach said.
“It’s all experimental,” Roach said. What he has found is that “the type of light is crucial” to the plant’s growth, he added.
Later this semester, radishes, mustard and another variety of lettuce will be planted, he said.
There are 36 plant beds in the hydroponic gravity panels, which are tables tilted to move the water and fertilizer down the beds. By the end of the semester, there will be 48 total plant beds in the hydroponic gravity panels, according to Roach.
Last semester, there were only 16 hydroponic gravity panels, he added.
The ARC was funded by a $30,000 one-year grant from the U.S. Department of Agriculture through the Virginia Department of Agriculture, according to Roach.
Ayers said an application was submitted for another $30,000 grant for the second phase but officials will not know until possibly October whether funds will be awarded. That phase would focus on improving production practices and addressing concerns about handling produce, he added.