Edited to add: I changed the title to broaden the scope of this thread; it will now be about all the aspects of my cabbage landrace development.
I’d like to start a cabbage landrace. We eat a lot of cabbage, but I have trouble growing it. The seedlings need to be started under cover due to the dry climate and erratic spring, and then the plants have to stay covered with rowcover to provide a humid microclimate and keep the cabbage aphids and cabbage worms off. (Otherwise, the inside of the cabbage becomes a disgusting mess.) But the humid microclimate provides a great environment for slugs and rots, so I often lose half of the plants under cover. I’ve never managed to get a fall crop of cabbages; going from our hot, dry midsummer to our erratic fall weather (we’ve sometimes dropped from near 100F daytime temperatures to freezing and snow within 48 hours, only to rapidly warm back up within the next week) just seems to be too much for them. Eventually, they turn mushy or fail to ever develop a head. In any case, the row cover is expensive, fragile, and non-renewable.
It seems like landrace development could solve this. For one thing, I’ve noticed that the pests don’t get into the head so long as the base is tight enough; if the base is tight, the damage can just be peeled off at harvest.
But to develop a landrace, I’d need to first get a bunch of different unadapted cabbages through the winter. I don’t have a root cellar. But I have heard that some people cut off (and eat) the cabbage head and only save the central core, stem, and roots. And I’ve had sections of brassica stem survive the winter in a cool compost pile.
So, I have two different ideas. Could I plant cabbages late enough that they wouldn’t form a head at all, but would be fairly large, and then just bury the whole plants under leaves or mulch? I know that I wouldn’t be able to select for heading that way, but this is just for the first year to get them through so they can cross; I already know they don’t work here.
Or, would it be possible to ask other gardeners in the area to save their cabbage stems after they’ve cut off the head? That way, I could get a bunch of different varieties (assuming they are open-pollinated) and the rot-prone head would be gone. Sure, the core would also be gone, but brassicas are good at sprouting from side buds, and I’d only need a few flowers to cross the first year.