Supplemental light differentially regulates indoor-grown basil (ocimum basilicum) growth, volatile compounds, and sensory attributes

Authors: KELLY, NATHAN - Oak Ridge Institute For Science And Education (ORISE); OEHLER, MADISON - Oak Ridge Institute For Science And Education (ORISE); Park, Eunhee; O'BRIEN, REGINA - Oak Ridge Institute For Science And Education (ORISE); Bai, Jinhe; Fonseca, Jorge; Luo, Yaguang

Submitted to: Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2025
Publication Date: 8/14/2025
Citation: Kelly, N., Oehler, M., Park, E., O'Brien, R., Bai, J., Fonseca, J.M., Luo, Y. 2025. Supplemental light differentially regulates indoor-grown basil (ocimum basilicum) growth, volatile compounds, and sensory attributes. Horticulturae. 11(8):963. Article e11080963. https://doi.org/10.3390/horticulturae11080963.
DOI: https://doi.org/10.3390/horticulturae11080963

Interpretive Summary: Basil is a popular crop often grown indoors in greenhouses and vertical farms, where its growth and flavor are influenced by factors like light, temperature, and CO2 levels. Basil’s aroma comes from chemical compounds that change based on the growing environment. To identify the best conditions for high-yielding, consumer-friendly basil, we tested different light treatments—adding extra blue, green, or far-red light. Far-red light caused taller plants with more leaves but reduced photosynthesis efficiency. Blue light produced shorter, more compact plants with better photosynthesis but less growth overall. Green light offered a balanced response, promoting moderate growth and more leaves. Light also impacted aroma, with Far-red light enhancing a citrusy scent and blue light leading to a milder aroma. Adjusting light conditions can help growers optimize basil’s growth, quality, and aroma to meet both producer and consumer preferences.

Technical Abstract: Basil (Ocimum basilicum), a widely cultivated herb, thrives in controlled environment agriculture (CEA) systems where light spectra can be precisely manipulated to optimize growth, morphology, and chemical composition. This study examined the effects of supplemental blue (BL), green (GR), and far-red (FR) light on two basil cultivars, Prospera and Amethyst, focusing on plant growth, photosynthetic efficiency, volatile compound profiles, and sensory attributes. The results showed that FR light significantly enhanced stem elongation and biomass accumulation, with stem height increasing by 82.7% in Prospera and 121.2% in Amethyst under FR light compared to BL light, and fresh biomass increasing by 32.6% and 66.5%, respectively. However, FR light increased photosystem II (PSII) efficiency by 34.3% in Amethyst compared to high-intensity white light, indicating FR light’s impactful role on growth and photosynthetic performance. Additionally, BL light improved photosynthetic efficiency by increasing electron transport rates and enhancing PSII activity. The volatile profiles were also significantly influenced by light treatments. FR light increased citral levels by 371.0% in Prospera, while allo-ocimene levels increased by 89.0% in Amethyst compared to the control. Sensory evaluations confirmed that basil grown under FR light was preferred for its stronger aromatic profile. In contrast, BL light reduced concentrations of certain volatiles, such as eucalyptol and eugenol, leading to a milder aroma. These findings demonstrate that the light spectra can be strategically manipulated to optimize basil’s growth, morphology, and aromatic profile, aligning production with consumer preferences.