The research is devoted to the development of technology of receiving nutritious solutions of the improved quality in plant growing of protected soil. The analysis showed that having watered with the balanced nutritious solution of plants in greenhous-es improves their growth and development, in-creases the productivity of vegetable cultures. The majority of systems of watering and top dressing of plants known now, and also mixing units for prepa-ration and supply of nutritious solution contain feed-ing pump, the main pipeline, the filter, a flowmeter, pipelines, electromagnetic valves, an injector, the manometer, capacities for preparation of uterine solutions, drainage network. The simplification of the design was reached due to using one pump which via the main pipeline and electromagnetic valve was connected to the network of watering pipes. The pump partially carries out the function of mixing of nutritious solution and the function of wa-tering pump. The increase of efficiency of the de-vice is possible by using several high-concentrated uterine solutions in common, and also the possibili-ties of precision correction of nutritious solution on batteries depending on production requirements. The mixing unit knot was as a result developed for the cultivation of plants in the protected soil, in ad-dition having sampler which exit via the backpres-sure valve was reported with an entrance to mixing collector connected via backpressure valves and peristaltic pumps with capacities for preparation of uterine solutions, and the sampler exit through fit-ting was connected by means of electromagnetic valves with a drainage network and sections of sys-tem of watering. Such design allows working in one of two modes: 1) watering with tap water; 2) water-ing with solutions of fertilizers and acids.