Hydroponics is a promising method for growing agricultural plants and is especially relevant in the context of global climate change. Microscopic algae, includingChlorella vulgaris, has great potential for use in hydroponic systems as natural growth stimulators. The effect of the suspension of an authentic strain ofChlorella vulgarisBeijerinck on the length of cucumber shoots and roots, as well as its dry biomass, was studied. During cultivation in a Knop medium with the addition ofChlorellasuspension, the length of the shoots was shortened from 11.30 to 8.15 cm, while the length of the roots also decreased from 16.41 to 10.59 cm. At the same time, the biomass of the roots increased from 0.04 to 0.05 g. The data obtained indicate the positive effect of the suspension of theChlorella vulgarisauthentic strain on the dry biomass of cucumber plants in hydroponic conditions and make it possible to recommend this strain for use when growing plants in hydroponic systems.