Has anyone else discovered worms in the bottom of their drip tray a day after watering, and do they hurt my plants.

Worms are beneficial in various ways. May just need air, like the others mentioned.

I use them in COCO and PM benefically. They just need a fabric pot to breath as they require oxygen. I believe worms in your media are even better than castings.

What are you growing in??

If you are using soil/compost/manure then he is a sign of good health and your over watering . . .

if you are in soil-less media I don't know that that is a good thing . . .

Good Growing