A system for making a vertical garden comprises a vase unit (20). The unit (20) comprises a bottom beam (42) which forms the bottom of the tub, two side walls (24). The bottom portion (44) leaves a drainage duct (80) free to allow drainage of the water for drainage of the tub. The tub is delimited by aluminium extrudates hooking to each other. The system is modular and economical to produce.