Cardboard helps suppress weeds, prepare new planting beds, and improve soil as it breaks down. However, more and more home gardeners are discovering that corrugated cardboard is a surprisingly useful material for maintaining garden beds. The reason is simple: it blocks sunlight from reaching weeds, protects the soil, and eventually breaks down completely. Creating new garden beds without digging—just a little patienceAnyone looking to turn a patch of lawn into a flower bed or vegetable garden doesn't necessarily need to reach for a shovel. Not all cardboard is suitableIf you plan to use cardboard in the garden, untreated corrugated cardboard is the best choice whenever possible.