May 18, 2023

LED lights help improve tomato yields

Research shows long-term exposure of far-red LED light in tomatoes can produce additional yields.

Research conducted by Philips Horticulture LED Solutions, Wageningen University & Research and Nunhems shows using far-red light can produce an additional yield of almost one-fifth in tomatoes, depending on the variety.

The far-red light needs to be added during the entire photoperiod alongside the standard PAR light, according to a news release.

As growers want to get as much as possible out of their LED lights, it’s why Philips Horticulture LED Solutions, a part of Signify, a Netherlands lighting manufacturer, in collaboration with its partners, is conducting ongoing research into the optimal light recipes and photoperiod (lighting duration) for different crops. The research has recently resulted in new insights for tomato cultivation, according to the release.

“It is well-known that the different colors within a light spectrum can have an effect on the development of plants,” Phillips officials said in the release. “In fact, crops may react differently to the various colors of light at different times of day. Therefore, this study sought to find the most appropriate time for the application of far-red light. They found that far-red was by far most effective when added throughout the entire photoperiod.”

While the outcome confirms the opportunities that far-red light presents , it is not a clear and straightforward equation. “We now have more insight into the impact of far-red light during different periods of the day. The next step is to focus on the ratio between far-red and PAR light (photosynthetically active radiation) to find the ideal balance between growing optimization and energy efficiency.” Erik Stappers, a Philips plant specialist, said in the release.

The best result was a 16% increase in yield, however, major differences between varieties make the outcome uncertain for growers, according to the release. The 20-week study shows all far-red treatments give more sink strength, which means that more sugars flow to the fruits. However, this only led to a significant increase in harvest if the far-red was dosed during the entire photoperiod — in this case 16 hours a day, according to the release.

The research partners conclude the plant is not more sensitive to the light in the morning or in the afternoon. Far-red light requires more energy than PAR light, which means that the long duration that far-red has to be added leads to higher energy consumption.

The question is the level at which the use of far-red becomes advantageous in relation to the extra energy consumption. If a relatively low percentage of far-red light produces additional yield, then the researchers expect it may become appealing. “We continue to tweak it to find the ideal light recipe for tomatoes,” Elena Jiménez, a Wageningen University plant pathology researcher, said in the release. “Besides additional yield in kilos, higher quality and better taste may also come into play in the future.”

Philips, Nunhems and Wageningen University have been working for seven years to research the ideal light recipe for tomatoes. Various light recipes are being tested in relation to energy consumption, light spectrum, additional yield and uniformity.

Based in Eindhoven in the Netherlands, Signify produces lighting for professionals and consumers.

TOP PHOTO: Research conducted by Philips Horticulture LED Solutions, Wageningen University and Nunhems shows using far-red light can produce an additional yield of almost one-fifth in tomatoes.