Potatoes were not the crop of the rich British landlords, they cared little for the Catholics who they regarded as breeding out of control.

During the years prior to the famine the landlords pushed more and more people from the best lands for failure to pay rent, grew more grain, raised more sheep, shipped these back home to England and watched the Irish starve more and more as their population tripled(? IIRC - it grew by a lot).

Few things about the former British administration of Ireland (or indeed of Scotland, Wales, or Northern England; the UK has never gotten the hang of regions even in modern times - before it left the EU, 7 of the 10 poorest regions in Northern Europe were in the UK) would lead one to assume competence.