Effects of LED Grow Lights on Indoor Arugula
Leafy greens and vegetables are popular because they are beneficial for human health. They are often found on the table in the form of salads. Lettuce, spinach, and arugula are three common leafy greens that are added to salad mixes. We have discussed the lighting requirements for indoor lettuces and ways to grow spinach at home. Today, let’s talk about indoor arugula.
The increasing demands and high market values of arugula attract growers to grow or produce it. Commercial arugula is grown in greenhouses or indoor plant factories with controlled environments. In greenhouses or indoor vertical farms, natural sunlight is supplemented or replaced with artificial lights. Compared to other artificial light sources like HPS lights, LED grow lights are more efficient and long-lasting. Furthermore, LED grow lights are available with various spectrum, which allows to set the optimal lighting for better quality and higher yields. Thus, LED grow lights are widely used in commercial arugula production.
But different light recipes which come with different flux intensity, spectrum, and photoperiods, make it more complex to target the optimal lighting for arugula. Since different light recipes have different effects on arugula, it is possible to achieve desired results such as increase nutritional content or boost yield by simply using different light recipes.
Increase nutrient content
Nutrient in arugula are beneficial for human health. With the increasing awareness of health and food safety, arugula with higher nutrient content is popular for health-conscious consumers. Growers are able to meet demands and increase nutritional content by using LED grow lights.
Searches have shown light spectrum can affect nutrient content. High blue and high far-red wavelength could affect the vitamin C content in harvest arugula. Vitamin C is one of the important nutrition that determines the shelf life. Higher vitamin C content in harvested arugula could extend the shelf life of the arugula. Searches also shown the interaction between light quality, intensity, and photoperiod on the nutrient content of arugula. Continuously lighting (24h) significantly increased the anthocyanins and flavonoids contents in arugula. It also increased the carotenoid content in arugula. Carotenoid processed antioxidant function that is beneficial for human health. The increased radish and other nutrient contents added nutritional value to arugula. At the same time, continuously lighting decreased the chlorophyll content in arugula as well. Chlorophyll content played a critical role in human perception of the green pigmentation of leaves. Luckily, the total decrease in chlorophyll did not decrease the overall visual quality of the arugula dramatically.
Reduce nitrate accumulation
It is well known that excessive intake of nitrates is harmful to human health. It is more serious for vegetables because about 75% of the nitrates consumed are provided by vegetables. Light has effects on the accumulation of nitrate in leafy and root vegetables. That is because photosynthesis determines the assimilation of nitrates in vegetables.
For arugula, its nitrate accumulation is also affected by light. Research has shown that higher light intensity of LED grow lights could reduce nitrate accumulation in arugula. With certain light spectrum, higher light intensity could reduce 13% nitrate accumulation in arugula. The reduction of nitrate accumulation in arugula helps grower to meet the low-nitrate requirements of different markets. In turn, growers are able to reap more profits. Except for meeting the regulation of nitrate content, lower nitrate levels can improve the taste of arugula as well. Lower nitrate accumulation has higher sugar levels, resulting sweeter and milder taste.
Improve yield
In general, arugula requires six to seven hours of full sunlight. It means the DLI (daily light integral ) is about or more than 15 mol/m2/day. However, plant factories or indoor vertical farms are lack of natural sunlight. In these indoor growing environments, LED grow light is vital.
Research has shown that both higher light intensity and longer photoperiod could improve yields in arugula. Under the lighting conditions of the same spectra and photoperiod, doubling the light intensity significantly improved the productivity for arugula from about 30% to 60%. They also showed the continuously lighting with higher light intensity improved the photosynthesis. The continuously lighting provided constant energy for carbon assimilation, resulting in larger biomass accumulation and yield. But the benefits of higher light intensity and longer photoperiod only occur when there is not injury. Apart from increasing productivity, continuously lighting accelerated the emergence of the first true leaf. It means that continuously lighting can shorten the time to harvest. The shorter production time also contributes to higher yields.
Conclusion
Spectrum, intensity and photoperiod of LED grow lights have significant effects on indoor arugula. They can increase nutrient content and reduce nitrate accumulation in arugula, as well as improve yields. By using optimal lighting recipes, it is possible to grow higher nutrient content arugula with a low nitrate content while having higher yields at the same time. To target this goal, selecting the right LED grow lights are critical. LED grow lights featured dimming function might be the best choice for indoor arugula. The dimming function enables growers to adjust the light intensity according to their needs. As a horticulture lighting manufacturer, Atop provides multiple dimmable LED grow lights for indoor arugula. We also offer customized lighting solutions for your greenhouses, vertical farms, and grow tents.
