I make manure tea for some of my chids. I put some horse manure in an old pillow case and tie it closed. I then sit this in a 5 gallon bucket of water and let it sit. I use it to water my high light plants like my Cyms. I imagine that you can do the same with worm castings. What I would be concerned about is not knowing how strong your solution is. Some plants may be sensitive to too strong fertilizer.