This work presents the design and analysis of tunable diffractive meta-gratings utilizing plasma technology. The proposed structures consist of arrays of cylindrical plasma discharges, each enclosed within a dielectric shield. Through both theoretical modeling and numerical simulations, we demonstrate how the propagation direction of transmitted waves can be dynamically steered by tuning the plasma frequencies of the discharges that form the meta-grating unit cell. A practical meta-grating capable of redirecting an incident wave from -46° to +46° relative to the broadside direction is designed and characterized. The reconfiguration is achieved while maintaining high transmission efficiency, highlighting the potential of plasma-based meta-gratings for adaptive and high-performance applications in the microwave range.