Shredded Corrugated Cardboard is another good source of worm compost bedding. Cardboard is thicker than paper so it takes longer for the worms to process it (eat it and poop it out!). Corrugated cardboard does a great job of leaving room for air and worm movement because of the space in each piece of cardboard. You can probably find a free source of cardboard (one large box will fill a worm bin). One drawback to using corrugated cardboard as your primary source of worm bin bedding is that it is difficult to shred or tear. You will make your hands sore tearing it up.