Rensselaer’s Greens grows life lessons

Have you ever wondered how fresh the produce at Commons dining hall is? There is an aspect to the dining halls that students are often unaware of. A 320 square foot shipping container just behind Commons dining hall houses a hydroponic farm run by Christopher Mansfield, the Supervisor of Hydroponic Operations at Rensselaer Dining Services. Last Wednesday, we visited Mansfield’s operation to gain a better understanding of the work he does and his contributions to Commons here at RPI. While Mansfield’s operation is currently centered on hydroponic lettuce served in Commons, he hopes to expand his operation to provide a larger variety of produce. Eventually, he hopes this will be able to contribute more to the campus dining halls.

The hydroponic farm’s history is rooted in Mansfield’s past, where he studied Culinary Arts in college. Being in the food service industry since he was 14 gave Mansfield a bit of background knowledge on hydroponic farming. He also devoted his time to studying different farming techniques and mediums as well as setting up the freight farm from the simple materials he was given in the shipping container. After muddling around with the idea, Mansfield’s pitch was approved at RPI in 2017. Since then, Mansfield has been able to grow his farm to about 130% of its original capacity.

While touring his farming operation, Mansfield offered a brief overview of how plants are farmed from their germination to harvest utilizing hydroponics. The plants start off in coir, a fibrous material made of coconut husks ground up and compacted into small cylinders. These are sustainable, compostable, and pH controlled, making them convenient for germinating plants. Once they have grown for a short period of time, they are transferred to Mansfield’s bottom trough, where they continue to grow until they start to sprout. After about a week, the new seedlings are transferred to the middle trough which are periodically flooded with water and nutrients to enhance growth. From the middle trough, the plants are transferred to long vertical planters called towers, which house them until they are harvested. The water and nutrients are delivered to the towers through a pipeline system along the ceiling of the space, and the nutrient mixture drips down through the towers, reaching all the plants before being collected and the bottom for reuse. Each tower housed 15 plants, making his farm’s maximum capacity 1850 plants. Mansfield emphasized that the farm only utilizes eight to ten gallons of water.

An interesting element of Mansfield’s operation was that it could all be operated remotely. With cameras and control equipment installed in the space, he is able to monitor his plants on his phone. For example, Mansfield spoke about the day-night routine of the plants. When we visited his farm in the late morning, the plants were still in “night mode,” meaning that their lights and water system were off. However, around 2 pm, the plants go into “day mode,” and the lights and water/nutrient system switch on.

One type of farming that Mansfield discussed was deep water growing, where the plant's roots are in a container full of water. This is especially useful for mustards and other plants which take a longer time to grow and produce large, complex roots which can clog the farming systems. Another technique for growing is the Kraky technique, where the plants are suspended above the nutrient-filled water, having an air gap instead of being completely submerged in water as in deep water growing.

In addition to various types of lettuce, Mansfield also grows the microgreens served at Commons. These are the most profitable because they are quite expensive to buy and provide at dining halls due to high labor cost. In contrast, Mansfield can easily produce them fresh and provide them to the dining hall at a relatively low cost. Overall, Mansfield estimates that he gets approximately 1.25 acres worth of yield from an entire year’s growth in his 40 by 8 foot shipping container. The shipping container’s ability to regulate temperature and energy draw allows the plants to grow in an organized fashion and avoid issues like fluctuating temperatures, the threat of drought or excessive rain, and pests.

Mansfield explained that if someone is buying a head of lettuce in upstate New York around this time of year, it has been about two to three weeks since the produce has been harvested and shipped to your grocery store. At that point, it is called “dead food” and has lost most of its nutrients. He pointed out that the nutrition labels on food account for the levels at the time of harvest, not what they have retained at the point of purchase. Compared to when Mansfield harvests his crop, he sends it directly to Commons and they use it within 24 hours, so it keeps its nutrients.

At RPI, Mansfield’s work on campus expands beyond just the freight farm, as he often presents to classes about his work on campus. Mansfield states that the farm has opportunities for everyone to contribute, not just students majoring in environmental-based studies. All students, regardless of major, can find an opportunity within the freight farm to cultivate skills, whether it be on the plants or the mechanics part of the farm. Mansfield hopes to spread awareness about the benefits of farming and teach students how to grow plants in everyday mediums. He points out how he understands students immediately jump into busy jobs after they graduate and wants them to understand how farming can serve as a relaxing outlook that can balance a heavy work schedule. In the future, he has hopes for not only the level of planting to increase, but for students to integrate planting into their lives so they can learn to grow their own plants.