[GpsFrontier]

A 3 inch hole saw probably won't work for 3 inch net pots, unless the pots have a exceptionally large lip. You'll want to cut the hole smaller than the baskets or they'll fall through. If you find a whole saw that will cut the right size hole for the baskets your using (so they don't fall through) that will work. Though most people seem to say that hole saws are difficult to use on rounded surfaces (like 4 inch round inch PVC or ADS tubing).

I have a lot of hole saws, but I prefer to use a rotary tool like in the attached pictures. When I need to cut a hole in plastic, that's the first thing I grab. It works great on everything I have done so far. However it didn't work that well on the blue 55 gallon drums I'm using for the Sub "T" system in my greenhouse. That was made of a very dense plastic, and the rotary tool worked on it, but kept breaking drill bits. With about 96 holes planed to cut, I thought about buying a adjustable whole saw (the only hole saw able to cut a 5 inch hole), but borrowed a jig saw that worked perfectly (and didn't cost me a penny to barrow).

P.S.
I bought that rotary tool at the swap meat 4-5 years ago for about $12. I didn't have a need for it at the time, just thought it would be a cool tool to have (especially at that price). But once I started building hydroponic systems, it has become the most valuable tool I have (other than my cordless drill).