Well-timed and reliable forecasting of grain yields is a key condition for effective crop management. In this research, we evaluated the effect of natural growth stimulants Epin-extra, Zircon and Bischofite on the duration of the main vegetation phases of spring barley varieties ‘Helios’, ‘Parnas’ and ‘Vakula’ of Ukrainian selection. Field trials were carried out during the period of three years (2017–2019). Their aim was to determine the most effective stimulant for growing different spring barley varieties under the conditions of unstable moisture. It has been established that pre-sowing treatment of seed and spraying of crops in the tillering phase with these stimulants help to reduce the vegetation phases and enhance the photosynthetic activity of spring barley crops. Application of 1% Bischofite aqueous solution provided the maximum effect. The treatment of crops with this preparation increased the area of assimilation leaf surface of plants by 11.1%, photosynthetic potential by 5.7% and the photosynthesis productivity by 10%.