Recovering and reusing resources from waste is a practical necessity for realizing sustainable development, while the lack of arable land and speedy release of fertilizer is also an urgent issue required to improve soil water and fertilizer conditions. Here, an eco-friendly biodegradable hydrogel was fabricated to serve as a slow-release carrier for nutrients that recovered from wastewater and investigated the potential role of it on vegetable growth. The hydrogel owned excellent water swelling and retention capacity, while degraded by more than 50 % within 11 weeks. Electrostatic interactions, hydrogen bonding, and ion exchange dominate the binding between nutrients and hydrogel, thus contributing to the maximum release period and efficiency for nitrogen, phosphorus, and potassium was 74.28 % in 21 days, 88.28 % in 28 days and 72.52 % in 7 days, respectively. Kinetic model fitting and molecular dynamics simulations indicated that the Fickian diffusion controls the release of fertilizers. Vegetable yields and root elongation were significantly improved by applying the slow-release hydrogel fertilizer, with yield increases up to more than two-fold at the second round of cultivation. Overall, this work provides novel insights into the reutilization of high-value resources from wastewater and agriculture sources to support a stable food supply.