Vermicompost tea seems to be kind of magical. It is high in microbial activity. We brewed large batches of it last year at the organic farm I interned at and both watered with it and used it as a foliar spray on our seedlings in the greenhouse. It effectively killed an infestation of insects that were attacking our tomatillo seedlings. So now, when I see that plants in my garden are being eaten by insects, or just don't look so well, I look to brewing vermicompost tea as a potential solution.
What you'll need:
1 cup or so of worm castings
5 gallon bucket of water
Cheese cloth or permeable material to make a tea bag with
Elastics or string
Fish pump with tubing
Fill the 5 gallon bucket with water. If not using rain water, let the water sit for 48 hours so the chlorine and other stuff from city water can evaporate before you brew your tea.
Place your worm castings on a doubled over piece of cheese cloth and wrap to make a kind of worm poo tea bag. Use elastics to tie off the ends securely.
I tied my tea bag to the handle of the bucket so it rested half way inside the bucket instead of sitting on the bottom, for optimal steeping.
I used an aquarium bubbler and attached it to the end of the fish pump tube and set it in the bucket of water. Plug in the pump and let it bubble for 24 hours. Some people add a little molasses to increase microbial activity but I have yet to try this.
Use the vermicompost tea within 24 hours after the brewing is complete, as it is an active solution.