Turkey has a large agricultural area and produces 55–60 million tons of biomass waste/year. This study aimed to obtain bio-briquettes from three types of dried greenhouse wastes and to determine their strength parameters. A prototype of a mobile briquetting machine driven by power take-off (PTO), with hydraulic pistons, and comprising a shredder and grinding or crushing unit with a briquetting pressure in the range of 0–190 MPa, was used. The physical parameters of the obtained briquettes were determined, including density, tumbler and shatter resistance, compression resistance, water intake capacity, and resistance to moisture-humidity. The results of physical and mechanical tests showed that the briquettes are of an extremely high quality. The maximum density, shatter and tumbler resistance were 1143.52 kg·m−3, 99.24% in pepper plant waste, and 98.52% in eggplant plant waste, respectively. Based on the analysis of compression tests obtained under 190 MPa (maximum compaction force of 450 kN), the maximum compression force, compression stress, and specific compression force were found in briquettes made from tomato plant wastes (3315 N, 69.43 N·mm−2, 40.09 N·mm−1, respectively). Overall, the results and variables affecting the strength parameters showed that greenhouse waste biomass is an excellent feedstock for the production of high quality bio-briquettes. The valorization of briquetted greenhouse waste with the proposed prototype contributes to the sustainability of the environment and to a reduction in energy costs for farmers.