The present research was conducted during the agricultural year 2022-2023 in the land of Byala Reka village, Parvomai municipality in central southern Bulgaria. The ground data for the yield was collected from an organically certified field sown with barley, which is part of the holding of ET "Borislav Slavchev". The BBCH scale for cereal plants was used to identify the phenological stages of crop development. Data from the Sentinel-2 satellite were acquired by the EOSDA LandViewer platform. Vegetation indices were generated in the same platform as selected ones used in relevant studies in conventional agriculture. Four images were used for the phenological phases BBCH-21 initiation of budding, BBCH-30 spindle, BBCH-51 grading and BBCH-77 end of milk maturity, respectively. Pixel values were extracted using the GIS software ArcGIS Pro. At the BBCH-99 technological maturity stage, ground samples were collected to measure biological yield. A correlation analysis was performed with the obtained ground and satellite data, establishing which vegetation indices are most suitable for determining yields and in which vegetation phase.