Efficient agricultural input is crucial for agricultural green production and sustainable development. The swift evolution of information and communication technologies has diversified the avenues through which farmers access information. However, how different information channels affect farmers’ production input remain poorly understood. Leveraging a two-way fixed-effects model and the Karlson-–Holm–Breen (KHB) method, this study delves into the mechanisms underlying the influence of both traditional and modern information channels on farmers’ inputs of seeds, chemical fertilizers, and pesticides (SCFP) based on over 15,000 sample of Chinese farmers. The findings reveal the following: (1) modern information channels significantly decrease farmers’ SCFP input, whereas traditional channels exhibit the opposite effect; (2) environmental pollution perception acts as a mediator in the influence of both traditional and modern information channels on farmers’ SCFP input; (3) traditional information channels significantly promote farmers’ SCFP input in the grain production and marketing balance areas, and modern information channels inhibit farmers’ SCFP input in major grain-producing areas; and (4) traditional and modern information channels have an impact on farmers’ SCFP input in the western region, but not in the central region. To promote sustainable agricultural development, government departments should enhance rural Internet access, diversify information sources, advocate for eco-farming, ensure regional digital equity, and enhance green agri-tech promotion.