Worm castings do not burn, therefore it can't be over applied.

One thing I noticed is that if you use catings on indoor plants there will indoor fungal activity. If someone is allergic to molds in the hous, this may become an issue. Don;t get me wrong, the fungus is what you want, it indicates a healthy soil, someone migh just be bother by the real thing...

Thanks for the responses!

occredneck
I know this must sound stupid, but do you mean fungus/mold will grow on the soil?

Thanks

Exactly. Last time I used castings in my houseplants I could see fungus growing in the soil. This is what the castings are suppose to be doing. It shows a well balance system of fungus and microbiological life.

I actually know nothing about worm castings.
Thanks for the information!

I make a 'tea' with my castings. Just water/castings in a watering can. I shake it up then I water my indoor/outdoor plants with that.