A survey done on worm casting shows that they are abundant in over 60 micronutrients including calcium, nitrogen, phosphorus, potassium, potash, magnesium, sulfur, and iron. Also, the NPK ratio for worm casting is 5:5:3.
The worm-casting nutrient content is higher than compost. For this reason, the rate at which worm compost is applied is lower and a single application works wonders. The worm-casting nutrient contains microbes that aid in plant disease resistance and deter harmful insects.
Worm casting is water-soluble and makes vital nutrients and trace minerals readily accessible to plants. They are purely organic making them essentially safe than chemical fertilizers.
Another great thing apart from the rich nutrient they provide, worm casting also retains moisture which is vital for plants to successfully pass through drought periods. They will as well enhance your soil structure and aeration.