Assuming the plastic and terracotta pots are bare, clean, dry, sound and prepared as detailed in the technical data sheet you could consider the products below. 

On the plastic we would recommend to test on a small area for compatibility and adhesion prior to full application.

Zinsser Bulls Eye 1-2-3 followed by Zinsser AllCoat Exterior (Water Based).

This can be mixed to many RAL, NCS or BS colours in a matt, satin or gloss finish. 

We would suggest to view a physical colour chart in person to ascertain a suitable colour match. 

We also offer Colour Sample Sachets.