Cactus‐Mimetic Atmospheric Water Harvester for Fog Collection, Condensation, and Direct Irrigation

ABSTRACT Atmospheric water harvesting is an effective method for obtaining fresh water. However, problems such as secondary evaporation from water separation and declining efficiency need to be addressed urgently. Here, we demonstrate a biomimetic cactus fog collector embedded in the soil that overcomes these challenges by integrating vortex‐assisted, multi‐level‐structured water transport and temperature‐difference condensation mechanisms. Our device integrates fog collection and condensation to efficiently collect water and enable immediate irrigation to the plant roots without requiring external energy. The cylindrical collector is fabricated using metal 3D printing, with a surface covered in conical spines of varying wettability, asymmetric through‐holes, and internal capillary grooves. In wind tunnel tests simulating coastal fog, the bionic design achieved a water production rate of 152 kg m −2 h −1 and a collection efficiency of 49%. In addition, we utilized the natural temperature difference between the soil and the air to achieve a passive condensation rate of 895.6 g m −2 h −1 . Field tests have shown that our system can sustain crop growth under water‐scarce conditions. Our work presents a new paradigm for atmospheric water utilization, from the development of biomimetic materials to integrated passive irrigation, providing a scalable strategy for agriculture in arid regions.