Cardboard boxes can be broken down and placed on the ground for excellent weed control; without sunlight the weeds will not grow. Some perennial weeds, especially those grasses with 'runner roots', although they will not grow under the cardboard, they will not be eliminated.
Most gardeners know that mollusks (slugs and snails) are a major pest. They are able to destroy seedlings and devour well-established plants.
Several control measures are available including chemical baits, trap boards, sanitation, even chickens and ducks. A trap board is a manageable size board, perhaps 12 inches by 12 inches, placed on the ground near slug and snail activity. Place one end of the board on a small rock, or another object in order to give it enough lift for the slugs to crawl under. This board then becomes a good hiding place for the slugs and snails which can periodically be scraped off and disposed.
Over time, the cardboard itself will breakdown contributing toward a healthy soil. Some white fuzzy growth on the cardboard are various species of fungi which help it decompose. They will not harm the plants and are a benefit to the soil.