Yeast extract (YE) is widely recognized as a biostimulant that enhances plant quality, stimulates growth, and increases plants' tolerance to environmental stress. As an environmentally sustainable and nutrient-rich product, YE offers several advantages over traditional soil conditioners and plant growth regulators. This has led to growing attention on YE as an alternative to synthetic chemicals in agriculture. In this greenhouse pot experiment, we evaluated the effects of different YE concentrations (0, 0.1, 0.2, 0.3, 0.4, and 0.5%) on carrot (Daucus carota L.). The primary aim was to examine how these YE doses, applied via soil, influenced growth parameters such as plant height, root length, shoot fresh and dry weights, root fresh and dry weights, and taproot diameter. The study also assessed YE’s impact on carrot color characteristics and soil properties like microbial and enzyme activity. Results showed that YE significantly enhanced carrot growth parameters (P ≤ 0.01), improved soil biological properties, boosted microbial activity, and created favorable conditions for plant development.