We planted a short row of Milva potatoes this year. Hadn’t tried them before, we usually grow some Yukon Gold, Norland, various fingerling varieties, and a blue potato. The Milva was a success, pretty good yield in so-so ground. Some grew to a fair size and appear to be more scab resistant than the other varieties. But some of the tubers had growth splits. That might have been a result of not watering regularly.
That’s a 6″/15 cm rule.