Compost is the start of soil health; recycling nutrients and building soil structure, improving water retention or drainage as needed. Making compost is also a cornerstone of green gardening; it's your very own on-site, biological recycling system and an integral part of your backyard ecology. At best, it's also very cheap, and good fun. Adding paper and cardboard to your compost heap is particularly important for stopping your compost being too wet or sour - technically speaking, it both aerates the mix and increases the carbon : nitrogen ratio. Practically speaking, it just happens to work very well and deals with yet more of your household waste.