So seed potato arrived today I have two varieties an early and a maincrop. Should I start chitting today? When should I plant them, should I stagger the planting? Any other tips and timings (I live in sunny reading btw).

depends where you are. chit the earlies now and aim to plant them middle to end of March. Plant the main crop in april, chit them first although to be honest chitting spuds will posibly only advance the crop by two weeks.

Chitting spuds sounds a painful condition – I’d go see a Quack.