"Red" Komatsuna – I didn't know of that variety choice. If you like Komatsuna, you may like Senposai, they are very similar/related.
I think that Winter hardiness may have to do with the conditions in which the crops are grown. Those conditions would include growing season weather. Several of the plants noted on the website have survived colder temperatures in my garden. That doesn't mean that I have made much of an effort to learn about this hardiness. The home veggie garden is very protected from wind by 2 garages, the greenhouse and a board fence. It is small and most of what I have grown has been on other people's property. That meant that I felt compelled to leave bare ground at the end of the growing season.
An example of where I see differences with the listing is with pak choi. Noting that they Winter-Kill at 25°f has not been my experience. Our Winters usually have some sub-zero F weather. If there are a number of plants - some may die. Others survive but bolt to seed as soon as the weather warms. We may still use the stalks for meals but, usually do not. BTW, the Maruba Santoh, Mizuna, Tokyo Bekana, and Tyfon Holland greens were things that I grew elsewhere and didn't leave them for Winter. Collards has certainly survived our recent Winters.
Interesting that Walla Walla onions are listed. I tried starting that variety 2 different years in late August, because I had read that is when onion farmers start their plants in the Walla Walla Valley. The first year, a good number of those onions bolted with warm weather rather than growing bulbs. The 2nd year, 100% of them bolted!
I should also say that I have not kept track of snow depth and plant survival.
Steve
