I sowed my maincrop potatoes in one of the raised beds on 30th March, varieties were Mozart, Maris Piper and King Edward. All the seeds were chitted and planted using exactly the same method, however, the Maris Piper & Mozart have totally failed to grow, I mean not even broken the surface! The King Edward were my own saved seeds from last year and they are absolutely thriving, unfortunately, after digging a few of the others out, the chits are the same size as when they were planted. The MP & M were bought from the supermarket, but saying that, I bought MP from the same supermarket last year and they grew ok?