The present invention relates to a method for producing sterile flowering biomass, the method comprising: a) inoculating a temporary liquid immersion culture system containing a sterile culture medium containing at least one cytokinin with sterile plant material, b) growing leafy biomass, and c) inducing and maturing flower tissues from the leafy biomass, wherein flowering is induced by reducing the duration and/or frequency of the immersion of the plant material in the culture medium in step c) compared to step b). It further relates to a method for producing a component present in flowering biomass, using sterile flowering biomass obtained using the aforementioned method according to the invention.