<p>Hydrogels are known as multifunctional materials that have been incorporated into fertilizers to improve crop yields, besides soil structure, and reduce water usage. Hydrogel-based controlled-release fertilizers (CRFs) have water retention and controlled-release properties simultaneously. They can reduce soil erosion, fertilizer waste, and nutrient loss compared to conventional fertilizers. Hydrogels also act as soil conditioners, leading to an increase in the porosity of soil and better air and water circulation. Regarding the great performance of hydrogel CRF as a sustainable solution for modern agriculture, some aspects of it, including definitions, various types (synthetic, natural, and semi-synthetic), properties, synthesis and preparation methods (matrix and coated), release mechanisms, economic factors, and their effect on plant growth, are reviewed in this essay. In general, modified natural hydrogel CRFs, as an environmentally friendly method, have shown good results in biodegradability, biocompatibility, affordability, and improving plant growth. However, various techniques, combinations, and additives such as biochar, nano clays, and/or synthetic hydrogels can be examined to reach better results and yields in the future. In conclusion, this essay reviews and compares various types of hydrogel-based CRFs from diverse aspects to encourage researchers to develop sustainable alternatives for future agriculture using natural resources.</p> Graphical abstract <p></p>