Is anyone sure what this phrase means?
Plant as early in the spring as the soil can be worked.
I'm not sure whether to interpret that as, "When the soil's no longer frozen, so you can turn it," or, "When the soil's thawed and no longer sodden," or... what. There's nearly a month's difference between thawed and no longer sodden. And thawed happens long before the last snowfall. (And semi-thawed happens multiple times.)
Seeds like spinach and sweet pea flowers give these instructions. I've read of people in the Northeast who plant spinach seeds during February thaw, and let them decide when it's time to come up. If the spinach seeds and seedlings don't mind repeated freeze&thaw, that would be the fastest way to have outdoor-started spinach, but you could do faster with indoor-started spinach. And for most plants, repeated freeze&thaw is more traumatic than staying frozen. Etc. It's just not clear to me whether I should put these out in early March, or early April.