Vertical farming (VF) has unparalleled capacity to highly customize plant growth environments. In VF, red and blue LED lights are predominantly used as the two main wavelengths for photosynthesis. For many plants, red light increases biomass, and blue light can increase nutritional content. Because red light is more cost- and energy-efficient to produce than blue light, refined growth recipes are imperative to mutualistically improve efficiency with crop yield and quality. This study's aim was to balance lighting energy-use with growth and nutritional quality by using "dynamic lighting" recipes to reduce durations of high-intensity blue light. Lettuce (Lactuca sativa L.) was grown for 21 days at 220 μmol m^-2 s^-1, receiving one of five R:B ratios (R:B_100:0, R:B_95:5, R:B_89:11, R:B_50:50, and R:B_0:100) for either the whole 18-h photoperiod (Whole Day), the first 6 h of the photoperiod (Morning), or the last 6 h of the photoperiod (Evening). Morning and Evening treatments received low blue (R:B_89:11) for the remaining 12 h of the day. The Morning and Evening high blue treatments had greater fresh weight and leaf area than their respective Whole Day treatments, attributed to reduced instantaneous leaf photosynthesis under high blue. High blue reduced photosynthesis during only the 6 h of Morning and Evening treatments, compared to the full impact of static high blue for 18-h Whole Day treatments. Intriguingly, with only 6 h of R:B_0:100, Morning and Evening treatments had the same high anthocyanin content as lettuce grown for 18 h under R:B_0:100. Therefore, daily blue light fraction can be reduced by using dynamic treatments to more efficiently promote growth and nutritional quality.

Plants respond to light spectrum in different ways. When using red:blue (R:B) lighting during cultivation, high R:B can increase plant growth and carbohydrates. Conversely, low R:B can increase phytochemicals and nutritional compounds. The aim of this experiment was to utilize dynamic R:B spectra to define this interplay between growth and phytochemical production by determining if spectral effects on growth are due to preferential carbon allocation to different phenylpropanoids. Here, lettuce ( Lactuca sativa L.) was grown under dynamic applications of high R:B (R:B _89:11 ) or low R:B (R:B _50:50 ) for three 9‐day phases. Plant growth decreased based on cumulative exposure to low R:B. Two groups of phenylpropanoids, flavonoids and anthocyanins, were induced under low R:B, with similar concentrations regardless of whether plants were exposed to low R:B for the final 9 days or all 27 days. Red lettuce preferentially produced anthocyanins over quercetin, whereas green lettuce maintained high quercetin. However, lignin, structural phenylpropanoids, and cell wall‐associated compounds were unaffected by R:B. Growth effects from R:B were instead linked to available energy from carbohydrates, which increased under high R:B. In conclusion, phytochemical content depends on the spectral conditions that plants receive during the final growth phase, while growth depends on the cumulative spectra. Using dynamic light application can therefore balance growth and phenylpropanoids.

Vitamin C, also known as ascorbic acid (AsA), is an essential organic compound that is crucial for both plants and animals. Due to the inability of humans and some other animals to synthesize AsA, it is essential for them to consume sufficient plant products, especially leaves and fruits, which are good sources of AsA. Numerous studies have attempted to understand how different environmental factors influence crop AsA development. However, a comprehensive understanding of how environmental conditions affect ascorbic acid development remains elusive. This challenge may be due, in part, to the inherent difficulty of accurately and consistently measuring plant AsA. Measurements vary significantly depending on the tools and techniques used to capture them, and consequently, comparing results from different studies is complex. To address this challenge, our study develops a regression model to predict the AsA content in lettuce based on different light conditions. By analyzing how the varying daily light integral (DLI) and the blue light spectrum affect AsA levels, the model provides actionable insights for optimizing light treatments. This model not only aids in enhancing the development of AsA in lettuce but also assists farmers in achieving more sustainable agricultural practices by identifying optimal light spectra and DLI, thus promoting efficient resource utilization.

Vertical farming (VF) has unparalleled capacity to highly customize plant growth environments. In VF, red and blue LED lights are predominantly used as the two main wavelengths for photosynthesis. For many plants, red light increases biomass, and blue light can increase nutritional content. Because red light is more cost-and energy-efficient to produce than blue light, refined growth recipes are imperative to mutualistically improve efficiency with crop yield and quality. This study’s aim was to balance lighting energy-use with growth and nutritional quality by using “dynamic lighting” recipes to reduce durations of high-intensity blue light. Lettuce ( Lactuca sativa L.) was grown for 21 days at 220 μmol m ^-2 s ^-1 , receiving one of five R:B ratios (R:B _100:0 , R:B _95:5 , R:B _89:11 , R:B _50:50 , and R:B _0:100 ) for either the whole 18-hour photoperiod (Whole Day), the first six hours of the photoperiod (Morning), or the last six hours of the photoperiod (Evening). Morning and Evening treatments received low blue (R:B _89:11 ) for the remaining 12 hours of the day. The Morning and Evening high blue treatments had greater fresh weight and leaf area than their respective Whole Day treatments, attributed to reduced instantaneous leaf photosynthesis under high blue. High blue reduced photosynthesis during only the six hours of Morning and Evening treatments, compared to the full impact of static high blue for 18-hour Whole Day treatments. Intriguingly, with only six hours of R:B _0:100 , Morning and Evening treatments had the same high anthocyanin content as lettuce grown for 18 hours under R:B _0:100 . Therefore, daily blue light fraction can be reduced by using dynamic treatments to more efficiently promote growth and nutritional quality.