LED Lighting Decreased Harvest Time For Tomatoes In Mans’ Experiment

Mans Organics' greenhouse

Mans Organics in South Alberta, Canada, was founded in 1994 by Henk and Rita Mans, initially using conventional farming practices. As they learned more about the impact conventional farming has on soil health and the health of consumers, they decided to go organic. The farm received its certification in 2007.

In 2012, their son Andrew came back to join the family business and built the farm’s first 1-acre greenhouse so that more vegetables could be grown year-round. Mans Organics planted and harvested its first crop of tomatoes, cucumbers and peppers in 2013.

Andrew, always looking for ways to improve the farm’s yields and revenue flow, looked at switching from high pressure sodium lights in the greenhouse—due to unreliability—to LumiGrow Pro 325e fixtures.

“You couldn’t ever be sure that your HPS were still working every morning,” he said. “Yes, they were under warranty and the bulbs could be replaced. But it was too many headaches when I needed the area to be at 100 percent.”

After a successful propagation trial of the LEDs, he ran an additional trial with his high-wire Long English cucumber crop. Mans was so pleased with how well the plants produced under the LEDs that he promptly put in an order for 70 Pro 650e fixtures to light 2,500 s.f. of his tomato production area. He also added LumiGrow smartPAR software so that he could adjust the lights’ spectrum and monitor the estimated energy usage.

Simple changes with big results

The tomato plants, however, didn’t do as well as the cucumbers. The young transplants were less enthusiastic about the low-light conditions, as they were accustomed to being transitioned to supplemental lighting at full capacity. Their leaves began to show early signs of stress and leaf damage. Thanks to smartPAR’s view mode, he was able to easily check on the plants’ leaf color and caught the issue early.

He reached out to LumiGrow for immediate assistance. LumiGrow Research’s support team quickly identified the issue and helped him put together a plan to ease the plants’ transition into higher-yield lighting conditions. As it turns out, various crops can require an escalating transition period when going from low light to optimal light environments. With LumiGrow dynamic LED fixtures, Mans was able to use smartPAR to dial back the red and blue light to 40 percent of their full capacity for five days, then increase to 50 percent for another two days. By day eight, he had all spectral channels at 100 percent of their capacity. This smart lighting strategy was deployed and ensured higher crop health through the transition—all new growth came in dark green and healthy. During production, Andrew went further to create a light program to “mimic the sunrise,” he said, turning the lights on at 50 percent of capacity for the first hour then back to 100 percent for the rest of the day.

When he harvested his first crop of LED-lit tomatoes in April, Andrew was able to harvest them a full 15 days earlier than his unlit tomato crop. This translated to shorter turn times and less time spent overall waiting for fruit to ripen, which allowed him to save on greenhouse heating during the winter months in addition to saving electricity on lighting. The LED-lit crop also had a higher yield than the unlit crop. All of these factors allow Mans to reliably scale his tomato production, mitigate big swings in Alberta’s weather and get his tomatoes to market sooner.

Long-term flexibility

Andrew Mans also has played with the spectral channels lighting his cucumbers. He noticed he was able to customize his crop—increasing the blue light combined with a 12-hour lighting period resulted in generative, short-noding plants. He then dialed back the lights to let the plants stretch and allow the fruit to grow in size.

In keeping with organic principles, he planted a wide variety of crops and maintains a crop rotation schedule in the greenhouse to maintain his soil’s health. The ability to quickly and easily reconfigure zones and adjust spectrum to meet multiple crops needs simultaneously gives Mans the freedom to pivot his business strategy as he chooses. For example, if he wants to use part of the greenhouse for propagation for a few weeks out of the year, he can set that area to a seedling-friendly light program, then switch to a higher intensity light program when he moves into production.

“The question of whether or not LEDs work has long been answered for me,” he says.


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About The Author

A word nerd, grocery geek and three-year member of The Shelby Report. She is a proud new homeowner and a great lover of avocado toast.

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