A-Head of the Rest: Lettuce Leaves Improved With Blue and Red LED Light

In many a garden around the world, lettuce is a prized produce. With crisp leaves and hearty in nutrients, lettuce is a ubiquitous ingredient in submarine sandwiches to Brunswick stew and everything in between. And as with any other agricultural product, lettuce depends on healthy doses of soil, water and sunlight for photosynthesis. But what happens when light is altered? And not even sunlight, but the plethora of LEDs that have come to market over the past decade? Is lettuce – or any vegetable and fruit for that matter – affected by extreme light in wavelengths other than standard white? According to research conducted and published by Chungbuk National University's Horticultural Science Department, the answer is an astonishing “yes.” In a recent study appearing in the journal HortScience, LED light altered the characteristics of lettuce leaf growth. Among the measured results was a drastic improvement in leaf size, an increase in antioxidant content, and greater production of flavor-giving molecules. "LEDs have the advantages of high light-conversion efficiency,” noted authors of the study Myung-Min Oh and Ki-Ho Son, “With low radiant heat output, semipermanence, and small mass.” In the study, researchers cultivated crops of green and red lettuce. Each variety was subjected to applications of six different LEDs representing various strengths of blue and red light. During and after the course of treatment, researchers monitored and measured the size of the lettuces’ roots, ratio of roots to shoots, area of leaf samples, and chlorophyll production. Not only did the LED light have an effect, but there was a marked increase in overall size of the heads with an accompanying growth in span of leaf area. In addition, researchers measured highly-enhanced production of phenolic and flavanoid compounds: a development which could result in lettuce of enhanced taste and aroma compared to traditionally grown lettuce, with the added bonus of being cultivated under nearly-normal conditions and absent of modification of the plant itself. And of further interest to researchers was that the treated lettuces produced far greater concentrations of antioxidants: a class of compounds that have long been much appreciated for the pro-cellular health and age-retardant characteristics of organisms digesting lettuce, including deer, and groundhogs, and run-of-the-mill humans. The Chungbuk National University team is already recommending using red and blue LED light together, in facilities providing closed growth of the plans, for consistent production of the improved lettuce crops. It is thought that not only lettuce, but other garden vegetables, may benefit as well. However, similar research into those crops has yet to be conducted. In the meantime, there is plenty from the new research to lettuce all be happy about!