If maintained properly, your worm bin will not smell bad. With the lid removed the compost should smell like earth. There should be no lingering odour around the worm bin. The key to maintaining an odourless worm bin is moisture control and oxygen. Anaerobic bacteria (the kind that thrive without oxygen) are the main cause of odour. If you don't allow proper air circulation or if your system is too wet, this kind of anaerobic bacteria will grow inside your worm bin causing it to smell. Making sure your worm bin contents are moist but not too wet, and that it has sufficient bedding material to keep it well-aerated, will ensure that no bad odours occur. See Worm Bin Moisture and Worm Bin Oxygen for more information on proper Nature's Wormery™ maintenance.
Posted in: How it Works / Feeding / Worms