One way to learn how to do something well is to understand how to do it wrong. Most of the time we get this by learning the hard way, or learning from someone who learnt it the hard way. I’ve compiled here some of the causes
overfeeding: top cause of death of worms especially with beginners due to misinformation or misunderstanding of information available online. Yes worms technically can consume their weight in food waste per day but that is only when all ideal conditions are met and maintained. In practice it’s best to keep it at around same weight in food waste per week. Giving too much food to the worms and hey won’t be able to consume them all fast enough and the food will break down, release a lot of water, fermentation kicks off, acidity and temperature raises, toxic gases are released, oxygen decreases and anaerobic conditions sets in making it a stinky wet mess.
temperature: too hot in summer, too cold in winter. High ambient temperature and overfeeding is a deadly combo.
moisture of the bedding: too dry for too long and the worms suffocate and desiccate, too wet and oxygen is also disappearing quick, this is why adding dry absorbant bedding material is so important, it reduce moisture while also maintaining its level for longer and increase bulkiness allowing a better airflow.
the type of food waste and their relative quantity: give one lemon to a Worm Café and it’s OK but give 2kg...
predators: mice, rats, geckos, birds, land planarians (flat worms)
sharp tools such as pointy rakes or shovels used to fluff a bin
food sources too rich in salt or ammonia like chicken manure or rabbit manure stained with their urine, fresh residue from composting with black soldier fly larvae etc...
some diseases maybe or what we call protein poisoning or string of pearl effect related to overfeeding
For a list of 10 biggest mistakes made by new Worm farmers, check this free PDF:
http://little.wf/e/10vermistakes
I hope this was useful, let me know or ask any questions in the comments below.