Potatoes (Maris Peer)

I grew potatoes three ways this year: (1) containers, (2) compost bags and (3) in the ground. The ones in the ground I expect have been nibbled on by little black worms and slugs like last year (I haven't dug them up yet), however, the ones in the container when harvested were small but pest free (the largest being about 3 inches long). In Northern Ireland I'm told that potatoes should be planted on St Patricks Day (easy to remember). This year I decided not to plant potatoes but then in early April I spotted a bag for half price that looked healthy so the '2nd earlies' ended up 'late' for me. Variety:  Maris Peer, Homebase, 2 kg bag for £3.49.