For most of them, hold them up and look carefully at the bottom. There is
usually a pot size number molded right into the plastic with raised letters
that gives the size. This number usually matches a diameter measurement
taken across the top of the rim. FWIW, if you come into my greenhouse I can
show you at least three pots that are stamped (6" Azalea) on the bottom and
they will all have slightly different physical measurement. This is true of
most pots. For plastic pots as with government regulations; there is no
legal governing authority.

"J Fortuna" wrote in message
news:dV80g.326$_s5.90@trnddc04...
I am trying to determine what size pots some of my orchids are in. Yes, I
know, I should know the answer to this already, but I am confused:

How does one measure a flower pot to determine its size? In a round pot
that is narrower at the bottom than at the top does one measure the upper
rim's diagonal or the bottom diagonal? What about in a square pot does one
measure the length of the side or the diagonal -- and again is it the top
or the bottom of the pot that counts?

Thanks!

Joanna