In protected cultivation, increasing the light level via supplementary lighting (SL) is
critical to improve external quality, especially in periods with low light availability. Despite wide
applications, the effect of light quality remains understated. In this study, the effect of SL quality and
nutrient solution electrical conductivity (EC) on growth and flowering of three bromeliad species
was investigated. Treatments included solar light, and this supplemented with R90B10 [90% red (R)
and 10% blue (B)], R80B20 (80% R and 20% B), and R70B30 (70% R and 30% B). These were combined
with an EC of 1 and 2 dS m-l. Irrespective of the light treatment, the higher EC promoted growth,
inflorescence emergence, and development in Aechmea fasciata (Lindl.) Baker, whereas adverse
effects were noted in Guzmania and Vriesea. The higher EC-induced negative effect in Guzmania
and Vriesea was slightly alleviated by SL. With few notable exceptions, SL exerted limited effects on
photosynthetic functionality. Depending on the species, SL improved external quality traits. In all
species, SL increased root and inflorescence weight and stimulated biomass allocation to generative
organs. It also accelerated inflorescence emergence and promoted inflorescence development. In this
way, the time to commercial development stage was considerably shortened. These effects were more
prominent at R80B20 and R70B30. Under those conditions, for instance, inflorescence emergence
occurred 3–5 weeks earlier than in the control, depending on the species. In conclusion, SL with
increased B proportion leads to shorter production period owing to faster emergence and improved
development of the inflorescence and is recommended for commercial use.