A head-to-head garden mulch comparison puts cardboard, pine bark, cypress, black plastic, and bare soil to the test across 175 days, tracking changes in soil temperature, moisture, and weed pressure. The results show differences in performance, including which mulches reduce weeds and a few surprises that shift expectations about which materials actually hold up over time. The results show the best mulch for the garden. Clear standouts emerge and reveal which mulches stay stable, which fall behind, and which ones deliver benefits for vegetable gardens.