1 CowPots: One cow can produce about 120 pounds of manure a day, creating a huge carbon footprint. But clever Connecticut farmers found a great solution for recycling great amounts of waste: making plant pots. No, they're not stinky, but they do release nitrogen as they break down in the ground. They're available in sets of 3-, 4-, 5- and 6-inch square and round pots, as well as six-cell flats. A dozen 4-inch pots cost $9.94 from www.greenhousecatalog.com. See www.cowpots.com for other retailers. 4 Coir Pot: Round and square pots made of coconut husk fiber are available at some garden centers. A dozen TerraCycle 6-inch coir pots cost $24 online.