<p>The pressing problem of increasing agricultural productivity and improving crop quality requires the development of new approaches to plant nutrition. One promising solution is the use of nanomaterials, in particular cobalt oxide nanoparticles (Co₃O₄ NPs), which are an important source of the trace element Co, essential for plants. The aim of this study was to investigate the physicochemical properties of Co₃O₄ NPs obtained using surfactants (cocamidopropyl betaine and alkyl dimethyl benzyl ammonium chloride) and evaluate their effect on the growth and development of pea seeds. Quantum chemical modeling showed that the interaction of Co₃O₄ with surfactants is energetically favorable (∆E &gt; 2950&#xa0;kcal/mol) and chemically stable (η = 0.035&#xa0;eV). FTIR spectroscopy, X-ray diffraction analysis, and scanning electron microscopy revealed the formation of a stable system with a cubic crystal structure (space group Fd-3&#xa0;m) and a particle size of 50–150&#xa0;nm, as confirmed by dynamic light scattering. The Co₃O₄ NPs were predominantly spherical and oval in shape, which is important for their biological applications. Biological testing of Co₃O₄ NPs on pea seeds showed a significant effect on seed germination and seedling growth. The optimal concentrations of Co₃O₄ NPs obtained using cocamidopropyl betaine as a template were ≤ 0.01&#xa0;mg/L, while those obtained with alkyl dimethyl benzyl ammonium chloride were ≤ 1.0&#xa0;mg/L. At these concentrations, increased root and sprout growth was observed. The observed effects suggest that the Co₃O₄ NPs may influence early seed development through surface-mediated interactions and gradual availability of Co. However, the present study did not directly assess release kinetics or Co₃O₄ NPs localization in plant tissues; therefore, the proposed mechanism should be considered hypothetical and requires further validation.</p>