One of the MVP’s of our nursery operation is our worms, specifically the Red Wriggler Worm. We have been vermicomposting by raising Red Wriggler worms since 2012 mainly as a kitchen composting assistant and as our colony has grown so has the amount of castings. Worm castings is just a fancy word for worm poop. As the worms process through the materials, they cast away a form of fertilizer that is loaded with nutrients and minerals that all plants love. Worm castings are a finished fertilizer unlike most animal waste, meaning that worm castings can be added directly to a plant or soil whereas other animal wastes such as chicken or steer manure need to be composted or aged before being added. Most commercial fertilizers are labeled with a ratio of Nitrogen, Phosphorous, and Potassium otherwise known as NPK ratio. Worm castings contain all of this and so much more.
Beyond the big 3, worm castings also contain Calcium, Magnesium, Humic Acid, and a plethora of beneficial bacteria to help your plants grow big and strong. They are naturally neutral with a pH of about 7.0 and also contain a miraculous pest repellant called chitinase. Chitinase is an enzyme produced in the digestive system of worms. Chitinase is named after its ability to break down the hard exoskeleton of many pest insects such as aphids, whiteflies, and many other hard-shelled bugs. Spread a 1-inch layer of worm castings around your plants and any bug that eats the leaves will in turn consume the chitinase and ultimately be dissolved from the inside out. Pretty ruthless way to die, but most gardeners I know grow plants and food for themselves not pests. You can also mix 1 cup of worm castings to 1 gallon of water and use this as a foliar spray fertilizer as well as a topical application of chitinase enzyme. Your plants will thanks you and over the course of 6 weeks you will have a created a natural pest free zone, all thanks to worm castings!
Another benefit of worm castings is its role as a soil amendment. If you have a sandy soil, worm castings will help with moisture retention and provide body or humus to the soil. It is recommended to add worm castings at the time of planting and should be re-added to the soil every 3 months for maximum benefits.