That's the thing; potatoes were given daily or even several times daily when they were available, which got really common. Limes/lime juice were rationed more carefully. I can't find the reference now, but there was even a British expedition to the Antarctic relying on limes that got stricken with scurvy, and it could not be explained why at the time.

Fermented cabbage products like sauerkraut were trialed and were successful, but weren't widely adopted, perhaps because of the Brits' tendency to cook it in iron cookware that gave it an unpleasant metallic taste.