I would think half a dozen. I have 13 in a 13 inch plastic pot. If they are happy they will spread - these 13 began from 6 about 14 years ago but can't recall what size pot they had then..They can be left undisturbed for years and just potted on when they need the space.

Thanks for that steragram info very much appreciated. :o)

Come to think of it I do give them a liquid feed when the leaves are there.

Thanks steragram.