"Improved control over DLI results in more consistent production and better odds of saving energy"

Lloyd and Candy Traven, who started Peace Tree Farm in 1983, have never been satisfied to maintain the status quo. The husband-and- wife team has seen their company evolve to ensure they are offering exceptional products. And they are always looking for new technologies that help them grow high-quality crops in a cost-effective way.

Basil, a major crop at Peace Tree Farm, is grown under LEDs controlled by the Candidus lighting control system during summer and winter to ensure plants stay short, dense, and stocky. In summer time, the LEDs are used for downy mildew control.

LEDs for basil
Peace Tree Farm grows basil, dill, parsley, cilantro, mint, rosemary, sage, thyme, and chives for Wegman’s Food Market in the Northeastern US. Basil accounts for 50 percent of the program. After finding that their HPS lights did not give them the quality they needed, they replaced them with dimmable Fluence LED fixtures. Peace Tree Farm now also lights most of its propagation area with dimmable LEDs.

“In the winter we use the LEDs to keep basil plants growing fast enough that it’s economical. In the summer we use the LEDs on basil more for the night interruption as a means of downy mildew disease control than for promoting more growth” said Alex Traven, who nowadays is co-owner of the company erected by his parents. This means that the lighting requirements change drastically, depending on the season. The Candidus lighting controller provides them the flexibility they need to account for the changes in seasons. 

Peace Tree Farm uses the Candidus lighting control system to provide night interruption lighting year-round for downy mildew control on basil plants.

Right amount of light
"With Candidus, they can ensure their crops get the right amount of light, while only using a fraction of the full power of the LEDs", says Mikhail Hutton with Candidus, adding that the Candidus controller provides other benefits as well. One area where the Travens have found the Candidus lighting control system to be an energy and money saver is with achieving the optimum daily light integral (DLI).  “One of the big strengths of the Candidus controller is that it can do the math based on a threshold of accumulated light that we are trying to reach,” Alex said. “If the weather is cloudy in the morning, the Candidus controller turns the lights on at 100%. If the sun comes out later in the afternoon, the Candidus system knows whether the plants still need additional light to achieve the desired daily light integral and keeps the lights on if necessary,” says Alex. “Similarly, if the sun is out and the light intensity is high, like during the summer, the Candidus controller runs the lights at a very low level or turns them off completely. If an afternoon storm rolls in at 5 p.m., the Candidus controller knows if the target DLI has already been achieved and whether or not the lights have to come back on. With the Candidus controller, we have a much better chance of hitting a specific light target and much better odds of saving a lot of energy in doing that.” In addition, the improved control over DLI results in more consistent production. This is critical since the Travens need to make weekly deliveries of their herbs to Wegman’s.

The Candidus controller is based on an industrial microcomputer and uses an Apogee quantum sensor to measure light levels in the greenhouse.

The Candidus lighting controller has an intuitive user interface that makes it easy to program it. The controller also shows the performance of the lighting system in real-time. Monthly reports, summarizing system performance and energy savings are provided.

Night interruption lighting
 “The vast majority of the summer we don’t need any supplemental lighting,” Alex said. “But the basil plants still need night interruption lighting for downy mildew control and the LEDs are really great for that.  A low intensity light level is enough to create this disease control effect. With the Candidus controller I can have the LEDs come on at 20% brightness. Since we are using night interruption lighting year-round, having the LEDs come on at a much lower light level provides us with an opportunity to save a lot of money.”

At Peace Tree Farm, the Candidus controller is used with dimmable LED fixtures. But the controller also can be used with non-dimmable LEDs of HPS fixtures. 

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