A simple, green, and fast approach (complete within 5 min) was explored for the fabrication of hybrid AgCl/Ag plasmonic nanoparticles under microwave (MW) irradiation. In this method, beet juice served as a reducing reagent, which is an abundant sugar-rich agricultural produce. Interestingly, the obtained AgCl/Ag samples have a smaller size than the AgCl reaction precursor. This makes it an unusual top-down hydrothermal synthesis. The as-prepared material displayed good photocatalytic activity for the degradation of methyl orange (MO) dye.