Hydrogels are attractive soilless media for plant cultivation with strong water and nutrient retention. However, pristine hydrogels contain mostly ultra-micro pores and lack air-filled porosity for root zone aeration. Herein we report a porous hydrogel composite comprising an agarose network and porous growing mix particle (GMP) fillers. The agarose backbone allowed the composite to sustain a 12-d growth cycle for red cabbage microgreens without the need for watering or crew interaction. Moreover, the GMP induced greater total pore volume and increased the prevalence of pores >30 μm by 8-fold. Further investigation suggested that the nutrients from GMP accounted for a 54 % increase in microgreen yield over pristine hydrogel, while the porous structure introduced by GMP improved the yield by another 44 %. Increased air-filled porosity accelerated the water transport and loss of hydrogel but maintained favorable water potential levels for plant extraction. Finally, the hydrogel composite supported microgreen growth satisfyingly under simulated microgravity despite some morphological changes. Results of this study reveal a novel growth substrate that is lightweight, convenient, and water-efficient, while effectively sustaining plant growth for multiple applications including indoor farming and space farming.

水凝胶是用于植物栽培的有吸引力的无土培养基，具有很强的保水性和养分性。然而，原始水凝胶大多含有超微孔，缺乏用于根区通气的充气孔隙。在这里，我们报告了一种多孔水凝胶复合材料，包括琼脂糖网络和多孔生长混合颗粒 (GMP) 填料。琼脂糖骨架使复合材料能够维持红甘蓝微型蔬菜的 12 天生长周期，而无需浇水或工作人员互动。此外，GMP 诱导了更大的总孔体积，并使 >30 μm 的孔的发生率增加了 8 倍。进一步的研究表明，与原始水凝胶相比，来自 GMP 的营养成分使微绿产量增加了 54%，而 GMP 引入的多孔结构又将产量提高了 44%。增加的空气填充孔隙率加速了水凝胶的水传输和损失，但保持了植物提取的有利水势水平。最后，尽管存在一些形态变化，但水凝胶复合材料在模拟微重力下令人满意地支持微绿色生长。这项研究的结果揭示了一种新型的生长基质，它重量轻、方便、节水，同时有效地维持植物生长，适用于包括室内农业和太空农业在内的多种应用。