Sheet mulching with cardboard is the secret to fewer weeds and fuss-free plant-bed prep.

Old cardboard boxes may seem like trash to some, but for gardeners in North America, they can be a valuable resource that helps to create a thriving garden while saving time, money, and effort.

Though this looks like some kind of insane mushroom growth, it’s actually special, die-cut cardboard strips put together by the Ball-Nogues Studio for an installation at Rice University. The artists ...