This 2021 study examined light frequency effects on Chinese kale sprouts’ development of glucosinolates:

“We investigated sprout growth and secondary metabolite glucosinolates (GSs) accumulation under white or combined red-and-blue (RB) light sources. Most GSs in sprouts are stored in seeds, which is gradually degraded to provide nutrients for other metabolic functions.

Phenotype of 3-day-old Chinese kale sprouts grown with different photoperiods condition under white or RB light:

Sprouts grown under dark conditions showed only elongation of hypocotyls [shoots]. Sprouts grew with shorter hypocotyls and wider cotyledons [first leaves] irrespective of whether a white or combined RB light source was used.

Growth indicators (including plant height, cotyledon length, fresh weight, and dry weight) under different photoperiodic treatments were measured on days 2, 3, 6, and 9. Consistent with the phenotype presented, plant height and cotyledon length responded rhythmically to illumination time.”

https://www.frontiersin.org/articles/10.3389/fpls.2020.589746/full “Effect of Photoperiod on Chinese Kale (Brassica alboglabra) Sprouts Under White or Combined Red and Blue Light”

Circadian rhythms rule. Accept and adjust.