There is provided a hydroponics device including a cover (14) forming an upper part of a cultivation planter (10) and a cover support (10C) supporting the cover (14) from beneath the cover and detachably connected to a pan (10B). The cover (14) supports plants (28P1, 28P2, 28P3, 28P4, 28P5 ... 28Pn), which are a predetermined number of different strains of the same species, so that tips (portions respectively including rootcaps and apical meristems) (28b) of taproots (28a) of the plants are immersed in a nutrient solution (LQ1) in the pan (10B).