Depends how big it is! I put 3 in a pot 15" across. (That may not be best practice, though!)

On a personal note! I prefer to put one bulb per 6"-8" pot.

At least this way the plants grows to suit the available light.

Putting three in could lead to an unbalanced arrangement as each bulbs fights for the available light.

This is exaggerated even more so if the plants are of different colours, or grow to different heights.

But as I said this is a personal view!

I'm not very experienced with these, Teegee - I've got some in single pots as well, so I shall see how they go!