In this study, Kolibri F₁ and Korist F₁ (Brassica oleracea var. gongylodes L.) kohlrabi cultivars were used as material. Plants were grown in the soil of an unheated plastic greenhouse. Seeds were sown in peat-filled multipots and standard cultural practices were done until the first true leaves appeared. The seedlings were transplanted into the greenhouse starting from the period when they had the first 4-5 leaves and were irrigated with salt water prepared at different concentrations in two different vegetation periods. For this purpose, four different doses of NaCl salt (Control, 5 dS m⁻¹, 10 dS m⁻¹ and 20 dS m⁻¹) were added to the irrigation water from the beginning of two different vegetation periods (from the young seedling period to the beginning of the stem, from the beginning of the stem to the harvest period). The experiment design was randomized plot with 3 replications. A total of 48 plots, 10 plants in each plot, thus a total of 480 plants in the whole experiment were used. As result, in parallel with the increase in NaCl concentration in irrigation water, an increase was observed in leaf damage index, while number of leaves (pieces), leaf area (cm²), stem diameter (cm), stem fresh weight (g) and marketable yield (kg da⁻¹) characteristics decreased. It was determined that plants were more affected by salt stress from the young seedling period to the stem beginning, also Korist F₁ was less damaged by salt stress than Kolibri F₁.