Sustainable lignin-based materials are becoming increasingly valuable in agriculture, where climate change and nutrient deficiencies threaten crop productivity. We developed lignin-derived cryogels using waste biomass to improve soil nutrients, seed germination, water retention, and photosynthetic pigment levels. These cryogels were synthesized with gum Arabic (GA), keratin (K), and N-vinylpyrrolidone at lignin concentrations of 0.02 wt.% (LbC1), and 0.1 wt.% (LbC2), along with a control (NLC), through low-temperature polymerization at -20°C. The cryogels exhibited high thermal stability and water retention, exceeding 170%, due to their network structure. Functional groups like carboxyl and hydroxyl enhanced nutrient assimilation, accelerating germination and plant growth, with keratin providing bioavailable amino acids through microbial degradation. After 5 days, the cryogel treatments significantly improved early germination rates (100%, 100%, and 99% for wheat, maize, and rapeseed, respectively), while boosting chlorophyll (a, b, and total), sugar, and soluble protein levels. Treated plants showed increased leaf numbers, plant height, and root length, with a 98.4% improvement in water uptake compared to controls, mitigating the effect of soil salinity. LbC1 and LbC2 also notably increased chlorophyll pigments, soluble sugars, and total protein across all crops compared to the NLC. Additionally, the cryogel exhibited a 33% biodegradation rate after 130 days in soil, confirming their environmental compatibility. In conclusion, the developed lignin-based cryogels represent a sustainable, effective solution to enhance nutrient availability and resilience in agriculture, repurposing industrial lignin waste to address climate-driven challenges in crop production.