I cleaned the concrete pot with a high pressure water cleaner, then painted two coats, i.e. all 250ml that was in the pot, less a smidge that I used to assist a yellow pot become orange.
I transplanted my French Sorrel from an unpainted pot, into this one.
I’m pretty chuffed with it, but before I do the next one, I will introduce additional preparation. That is, after cleaning with the high pressure water cleaner, do a coat of sealer and or white acrylic paint so the colour will be brighter.
Blue will be next I think, or perhaps purple.