Hydroponic gardening involves growing plants indoors, in a water-nutrient mix. Kendal recently launched a promising experiment with hydroponics. But there is another retirement community less that an hour away that has been at it for more than five years, and a group from Kendal went there on a field trip in mid-November. Our group consisted of nine residents and John Platt, Kendal-Crosslands Director of Culinary Services.
The retirement community is called Garden Spot Village, on the outskirts of New Holland, a small town just east of Lancaster, PA. Garden Spot Village has over 1,000 residents, making it significantly bigger than Kendal and Crosslands combined. It has a hydroponic greenhouse where virtually all the salad greens for the community are grown, along with herbs and a sampling of vegetables, such as beans and tomatoes.
The greenhouse was initiated by Steve Lindsey, the CEO of Garden Spot. It was built in 2015. It differs in several ways from the approach you can observe in the “hydroponics lab” in the lower level of the Kendal Center. It is much bigger, of course (about 4,000 square feet). It is a glass-roofed greenhouse, depending on sunlight rather than “grow lights”. (The small beds where seedlings are sprouted do use grow lights, however, and Garden Spot may add grow lights throughout the building to help maintain production during gloomy winter periods.)
Plants in towers. Instead of horizontal tubs, like those in the Kendal Center, Garden Spot uses vertical columns (called “towers”) with nutrient-laden water running down the inside. There are slots in the sides of the towers into which individual plants can be placed. The towers are 10 feet tall. There are 24 of them, and they can accommodate about 18,000 plants. A pump in the base sends the water to a shower head in the top of each tower for 15 minutes of each half hour, and the water rains down the inside of the tower, moistening the roots of all the plants. This is an uncommon approach to hydroponics—there are only eight facilities in the US using towers like these.
Steve Heydt, who is in charge of the greenhouse, showed us around and answered our questions. Planting and harvesting is mostly done by resident volunteers, who work for an hour or two on Mondays, Wednesdays, and Fridays. There generally 3-5 volunteers working on each of those days. Far more people are interested in volunteering than Steve can actually use. Steve himself does the planting and harvesting of plants near the tops of the towers, because residents are not permitted on the ladders (for safety reasons).
What does it cost? Since we are interested in exploring the possibility of scaling up the Kendal hydroponics effort, we had lots of financial questions. Steve Heydt patiently answered as many as he could. The capital cost for the building and equipment was roughly $1 million. Steve’s annual budget (including a share of his own salary as well as the cost of running the greenhouse) is around $23,000. Of that amount, $13,000 is for utilities.
The greenhouse uses natural gas for heating (using hot water circulating under the floor) and electricity for the pumps in the towers. The greenhouse is allocated a share of the cost of these utilities, but it does not have separate meters, so there are no exact figures on what the greenhouse utilities cost.
Steve doesn’t know whether Garden Spot is saving money, compared with what the kitchen would be paying for greens from an outside supplier, but he emphasized that freshness and the involvement of the residents were important non-financial benefits. John Platt noted that Kendal-Crosslands pays about $350,000 per year for produce, so it seems likely that the greenhouse makes sense financially. On the day we were there, around 50 pounds of greens (mostly varieties of lettuce) were harvested, and that seemed to be a typical day’s harvest. But since the plants are weighed and sent to the kitchen with their roots still attached, the actual usable weight would be significantly less than 50 pounds.
Steve mentioned a return-on-investment analysis done by the Tower Garden company, which makes some of the equipment. It can be found at https://www.towergarden.com/blog.read.html/en/2015/8/tower-garden-yield-value.html In this study, which is addressed primarily to individuals growing plants at home, the project pays for itself in 6-12 months. The study includes the costs of utilities, seeds, and nutrients, but does not include any labor costs.
We came away from our visit to Garden Spot Village with lots of great ideas and with a sense that our prototype hydroponics lab really could be scaled up to serve the whole community with greens. But we didn’t learn much about the degree to which it might save money or reduce our carbon footprint—that part will be up to us to figure out.