According to the USDA
Natural Resources Conservation Service, worms digest the plant material they ingest and concentrate the nutrients in their castings. Their castings are extremely rich in phosphorus, nitrogen, potassium, and magnesium.
They also contain live organisms, like actinomycetes, fungi, pseudomonads, beneficial bacteria, yeasts, plant growth regulators, molds, and trace elements. All these elements work together to create a favorable environment for plants and stimulate their growth.
Worm castings tea is a liquid form of worm castings that allows you to spray it onto the ground or directly onto plants!