If you want to stretch the use of worm castings over an extensive garden, or your front lawn, there's a fairly simple process to turn the solid vermicast into a liquid fertilizer that can be poured or sprayed on your garden and lawn.
"Worm tea" is produced through a cold-brew, oxygenated process and allows you to grow the good microbes in your castings exponentially.
The process can be as simple as putting a half a cup of castings into a 2-liter bottle, and shaking it up several times a day, then leaving the cap off the bottle. In about 2 days' time, you will have a wonderfully nutritious (for plants) muddy solution you can pour right onto the soil at the base of your plants.
A more involved process involves brewing for 36-48 hours with an air pump that continuously stirs the water so it remains oxygenated. We use this process (seen above in the video) and add a tablespoon of kelp extract to further feed the microbes. We then strain the liquid, so it's not muddy from the castings, and you have an easy-to-use, all-natural liquid fertilizer.
Two important cautions:
First - because it's a living material, worm tea is highly perishable, and should be used within 4 hours after the brewing process ends. You want to make sure you are feeding the plants aerobic microbes (not anaerobic). Once the active brewing process ends, if there's no oxygen introduced into the water, the smelly anaerobic bacteria that are not good for plants can begin to grow and take over the mix. (In the 2-liter bottle example, you leave the cap off most of the time, and close it only to shake the contents. The shaking helps ensure oxygen is maintained throughout the water.
Second - understand the difference between worm tea and leachate. Leachate is the liquid that may come out of the bottom of your worm bin, and while it might not be harmful to plants, there's no way to know without a chemical analysis, and the chances are high that it's full of anaerobic bacteria. A well-run worm bin won't produce any leachate. If you're finding a lot of water draining from your bin, it's time to add a lot more bedding material to soak up that moisture.