I've never had any luck with pebbles - especially if it's going to sit outside - you will have an overflowing wagon everytime it rains. The plants will do much better with drainage holes. That's what I do.
Arlene

Thank you so much Arlene :) I love your creations-have not seen anything like it around here (SC). God Bless :)

I also have better luck with drainage holes. I know it seems like you are "damaging" the piece , but once it's a planter it will probably be a planter the rest of it's life.

Drainage holes work best for me too!

Thanks everyone:)