The present study comprises comprehensive research of red, green and blue light emitting diodes (LED), which are widely used in phytoirradiators for plant growing in protected ground in the environment of a photo-culture including their spectrum measurements within the wide range of current values at room temperature. Shifts of spectral peaks of radiation of red and green LEDs after increase of operating current were discovered. On the basis of the conducted study, recommendations for selection of current operating mode of light sources used in phytoirradiators for plant growing in the environment of photo-culture were worked out, and a model of a phytoirradiator was proposed and studied in this work with red, green and blue LEDs, which have their spectrum covering all regions of photosynthetic active radiation (PAR).