The aim of this study was to determine the effect of treatment with Rivergreen® on growth and development of kale seedlings. Rivergreen® is a new product obtained by milling and tribomechanical activation of the Drava river rock sediment. The research was conducted during 2018 at the Laboratory for Vegetable, Flowers, Medicinal and Spice Herbs at the Faculty of Agrobiotechnical Sciences Osijek. Two varieties of kale, cv. Kapucinski and cv. Željezna glava were used in the study, following the growth and development of the kale until the transplants stage. It was found that Rivergreen® did not have a significant influence on the fresh and dry mass of cv. Kapucinski, while it had the same effect on cv. Željezna glava varieties, where the significantly higher fresh and dry overhead mass measured at Rivergreen® seedlings was significantly higher. It was also found that the number of leaflets of the cv. Kapucinski variety was greater under the influence of Rivergreen® treatment. Number, width and length of leaves in the cultivar Željezna glava head was not affected by the treatment with Rivergree®, while the difference in the number and length of leaves in the cv. Kapucinski variety was apparent. The leaf width in the specified variety was not affected by Rivergreen® treatment. Treatment with Rivergreen® influenced the height of the stem in the cv. Kapucinski variety, while the difference in height was not visible in the cv. Željezna glava variety. From all of the above results, it can be concluded that Rivergreen® in most of the observed properties has a different influence on varieties. Further research is needed to determine the true effect of Rivergreen® on final yield and quality of kale.