Year-Round Greens (With Science's Help)
Freight-container farms may be agriculture's new frontier
Sarah Ward has found the perfect job for a young mom concerned with what her children eat. She waves her hand and says, “Welcome to my farm.” We are standing in the backyard of her suburban Nashua home. Tucked between the garage and a wooded area is her farming operation — a 40-foot freight container painted a quiet shade of green.
Inside, plants in various stages of growth are basking in the eerie pink-violet glow of LED light. There’s not a drop of soil in sight, only a multitude of hanging verticals and evidence of some high-tech feeding systems keeping the greens alive.
Sarah and her husband Chris bought the farm this past spring, and, within several months, they were selling pristine lettuce, kale and herbs at the local farmers market as Oasis Springs Farm. She has no degree in agriculture, just a deep abiding faith that this venture was efficient, ecologically sound and a good way to work at home. In fact, most of the work can be done when her youngest is in nursery school two days a week. Chris works full-time elsewhere but lends a hand with technical advice.
Freight-container gardening was developed by a small Boston company, Freight Farms. The concept is elegant and turnkey. They purchase used freight containers designed to protect food contents for shipping; they are already properly insulated. The interior is retrofitted with a hydroponic growing environment, including sophisticated sensors, a watering system that recycles water on cue, and strings of blue-and-red spectrum LEDs that dangle between plastic vertical towers hung on rails.
The LEDs are the key to the success of the LGM — Leafy Green Machine — as it was affectionately named by Freight Farms. The energy consumption of the light source is relatively low, plus Sarah uses a day/night shift for the plants, meaning she runs the lights at night when costs are lower. The lights need to be on for about 16 hours a day to grow at an optimum rate. The blue and red combination creates a violet that best mimics the quality of light from the sun, at least for leafy green plants.
Plants can be grown year-round in the container, which is heated, in part by the LEDs. Plants that traditionally thrive in spring are perfect for this system, as the interior temperature is kept at 62 to 65 degrees — though sometimes, even in winter, it takes an air conditioner to keep it cool.
Growing healthy foods close to the marketplace was another important factor for Sarah. Hydroponic systems are closed — there’s no need for pesticides or any other pest management practice. It takes two acres of land to produce what can come out of the freight container. Also, hydroponics use 90 percent less water than conventional farming. Instead of irrigating an entire field, water enriched with nutrients is delivered to the plants three times a day. A layer of cotton in the towers holds the water, and any excess water is recycled.
The growing cycle for the young, green plants takes about seven to eight weeks. Sarah drops seeds, mostly from Johnny’s Seeds, into a growing medium where they are incubated for about a week while they sprout. Then the tiny seedlings are placed into a peat moss-like medium to grow for another two weeks. Finally, she transfers the plugs to the vertical system. There is even a special shape in the workbench surface to hold the tray while the plants are squeezed into the inert, sponge-like medium that holds the plants in place while growing sideways.
The trays are hung vertically in two sets of two rows. Between the rows are strings of lights, the “sun” that allows the plants to develop to maturity in about four weeks. When ready for harvest, the baby lettuces, along with their plugs, are removed. Some of the plants, such as mustard greens, can be trimmed four times. Sarah keeps track of the harvest dates with magic marker notes penned directly onto the plastic towers. In total, there are 256 towers to manage, and Sarah estimates she can deliver 1,000 heads of baby lettuce a week.
Taking her product effectively to market will be the key to Sarah’s success. As a former marketing major, she has developed attractive packaging, and she’s reaching out to local restaurants and grocery stores. She made an appearance at the Nashua Farmers Market at the end of the season to sell directly to consumers. Currently, Oasis Springs Farm is offering a CSA share program that starts in January and runs for 10 weeks, offering full- and half-share options with lettuce heads, greens mix, salad mix and herbs.
Vertical farming may be the best practice for sustainable growing now and in the future. Without environmental constraints, “farms” can be located anywhere from a parking lot to a rooftop to a suburban backyard. Shipping distance is minimal, and the produce is clean and tasty. Maybe more important, it helps you follow the advice of nutritional gurus and mothers everywhere to eat more leafy green vegetables. Sarah sums it up, saying, “This is a way to better our society, one leaf at a time.”