Optimal Ratio of Red and Far-Red Irradiations for Cucumber Plants Growing by Light-Culture Technology

The article presents the results of 12 full vegetation of cucumber plants of the variety “Svyatogor F1” by light culture technology. The studies were conducted on an experimental hydroponic plant at photosynthetic photon irradiance of (200 ± 10) μmol/(s‧m2). The methodological approach to the photobiological studies was developed together with the specialists of the agrotechnical complex “Teplichnoye”. In the experiment, LEDs phyto-irradiators with adjustable radiation spectrum were used, which allowed us to study the effect of the ratio of red (600–700) nm and far-red (700–780) nm radiation levels on the growth, development, and productivity of cucumber plants of the variety “Svyatogor F1”. The results of the experiment showed the greatest efficiency of biometric and productive indicators of these plants on variants of irradiation by LEDs with the addition of far-red radiation to the red at a ratio of levels of the first and second from (30/70) % to (60/40) %; while increasing the proportion of far-red radiation up to 70 % and more inexpedient.