Posted: 14/05/2016 at 07:36
The smell left behind will encourage your cat to go back to that place; after all I was taught to litter box train the cat by putting their poo in the box so you might be worth at least removing an inch or two and maybe putting gravel / slate on the pots to protect them.
What you also need to them address is where will your cat go now? Will you be encouraging them to use a provided tray of loose soil somewhere nice and discrete that you can clean up easily? Perhaps with a cat nip type plant nearby to encourage them that this is their area of the garden.