Hi All!
I use a diamond tip hole saw. I can't find the tutorial video I originally used, but here's another site that may be helpful to you.
http://gardeningonadime.com/dr...
I've put holes in terracotta and ceramic pots. It took a few tries to get started, but use some water and you have to start at an angle to sorta chip the pot to get started and then patiently drill the rest of the way through with controlled pressure, making sure there's some water in the hole. Note: If you're putting too much pressure on the drill and the hole is created before you realize it, you risk smashing the pot w/your drill. I may, or may not, be speaking from experience ; )
I purchased my drill bit at Lowe's. I can't recall the diameter I purchased, but I could check if you'd like. I recall Amazon had sets, which would've been ideal, but I believe they were shipped from China and I had some new pots from an estate sale that I was anxious to get holes into. The planter possibilities are endless : )
