Global food systems currently face critical pressures from population growth and shrinking agricultural resources, necessitating a transition toward nutrient-dense and spatially efficient production models. Microgreens have emerged as a promising solution; however, their sustainability is largely dependent on the choice of growing media. This review synthesises the biological and systemic requirements of microgreen cultivation with a particular focus on the transition from traditional soil and synthetic substrates to biodegradable natural fiber mats derived from hemp, jute, coconut coir, and agricultural byproducts. The analysis explores the comparative agronomic performance, operational advantages, and environmental impacts of these bio-based media. Furthermore, it evaluates the dual-application potential of these fibers as field-scale mulch sheets for weed suppression, highlighting their role in reducing reliance on synthetic herbicides and plastic films. By integrating diverse biomass sources such as rice husks and water hyacinth into a circular-economy framework, these biodegradable materials support a resilient, low-carbon food production lifecycle accessible to both commercial and household-scale growers.