As the (aspiring) cabbage steward for GtS, I’m starting a thread for the 2025 cabbage projects. Last year, I distributed a diverse mix of cabbage seeds to participants; how are they doing for people? Who has overwintering cabbages, and how are they doing? What are people’s plans for planting this year?
My bed of cabbages are still alive under row cover and a mulch of leaves. I’ve been putting a plastic sheet over the leaf mulch whenever precipitation is forecast, and taking it off during sunny weather. A week ago, I looked underneath and most of the cabbages are still alive, but the next month or so will be challenging. It will warm up enough that I will have to remove the mulch, but we also get repeated cold spells through the beginning of May, which can kill of new growth. Last year, I lost overwintering plants during the spring after they had successfully survived the winter; the repeated freeze-thaw was just too much for them.
I uncovered my cabbage, which had been overwintering under rowcover and leaves, because with the warm weather it was starting to sprout under cover. The problem is going to be getting it through the cold spells we will probably get through April; Colorado’s spring weather is very erratic, going from warm sunny days in the 60s and 70s back to winter-like conditions; March and April tend to get a good bit of snow, and temperatures in April can fall into the low teens or below.
As can be seen in the picture, most of the cabbages I planted last fall made it through the winter, some in better condition than others. Even if a lose some in the next few weeks, it should be a good foundation for a grex.
Wow, this is so cool. I’m still quite new to gardening, especially seed saving and overwintering veggies, and it’s amazing to see how resilient some plants can be. Those are some hardy cabbages.
It sure was great to pull back the cover and find most of them still alive!
One thing I’m a little concerned about is that some of the hadn’t made a head, and none of the had had time to create a really solid head before they stopped growing in the autumn. I hope they were mature enough to go to seed this year.
Here is a picture of an overwintering cabbage in my garden which is starting to put up a seed stock.
This one wasn’t in the earlier picture I posted, because it was the sole survivor from my 2023 cabbage overwintering experiment, while the others were planted in 2024. I had grown a number of different cabbage varieties and buried them in mulch, but they rotted or were eaten by slugs. This one plant came back from a tiny side shoot; it was from a Belarusian Grex that I got from Peace Seedlings. I nicknamed it “lonesome George” after the famous tortoise.
It didn’t flower in 2024, probably due to its weak start, which is just was well, since Brassica oleracea are self-incompatible (they won’t set seeds without pollination from another plant.) Instead, it grew three small heads on fairly long stocks. I gave it and the rest of the cabbages I planted in 2024 much more protection this winter, and it came through in fairly good shape. Now it is getting ready to flower well in advance of the other cabbages; I may keep the flowers pruned off until the other ones are flowering.
I didn’t set out to work on cabbage, but this filderkraut has now overwintered and stump sprouted twice after producing nice big cabbage heads and it appears to be preparing to make a third head this year, so I let a secondary stem from last year go to seed along with my leafy kales and collards this spring. It’s the only heading cabbage in the patch, so all of its seeds should be crosses and will need to be grown out and crossed again with their siblings or back-crossed with this mother plant if I want to recover the heading trait. I’m not sure I’ll do that, but I’m at least planning to sow a row of seedlings and see if anything interesting shows up. Would love a dazzling blue style filderkraut!
The second head of cabbage this plant produced when it stump sprouted in its second year.
Potential crosses include: Dazzling blue kale, Cascade glaze collards, red Russian kale, a collard type brassica I collected seed from growing wild along the SW Coast Path in Cornwall, and an heirloom tree collard line I have multiple specimens of in the patch. It overlapped in flowering period with all of them, but the most likely crosses based on proximity and flowering period are with the Dazzling Blue kale and the wild Cornish collards.
Last week I dug up these cabbage plants and now they are in the fridge for 2 months until mid August when I will plant them out again. The plants are various heirlooms. My goal is that they will skip the heading stage and go to seed this year. My goal is to produce a lot of genetically crossed, diverse seed this year (and share with GTS).
Maybe repeat this same process again in 2026 to get some F2 seed. Then have a big grow-out year in 2027 to select for overwintering and save seed in 2028 from whoever survives that. Maybe. I don’t know–one year at a time.
I started the seeds on a damp paper towel in a plastic bag, at room temperature for 2 days, then in the fridge for 2 weeks to vernalize the seeds. When I removed them from the fridge they were sprouted. This step could be skipped but some of the research shows that vernalizing the seeds can later cause more flowering in the plants.
I found a bunch of research articles floating around the internet on the topic of “artificial vernalization of cabbage” so I have applied those ideas here. In theory this should work. The cabbage plants must be past the juvenile stage before they are vernalized or overwintered. This means that the stem is at least as thick as a pencil, or that the plant has at least x number of leaves (with x varying by variety). The 6 plants in the top left corner have stems that are not quite as thick as a pencil, so they might not seed. Time will tell.
Sprouted seeds were planted in a cold greenhouse on March 3, then transplanted outside March 28, and endured some cold weather. Probably would have been happier to stay in the greenhouse longer, but we’ll just call it “selection pressure.”.
Rachel, this is very interesting! Please keep us updated on your work; this could greatly speed up cabbage breeding. Were any of the original seeds from the mix I was distributing?
Avery, it will be interesting to see what comes out of such wide crosses. The Russian kales are mostly B. napus and so would be less likely to cross. Also, it is cool when cabbages come back and create multiple heads in the second or third year; did your filderkraut ever produce seeds in past years? I wonder if a plant would survive seed production.
That was my thought, too. Wasn’t planning to make the crosses, but then figured why not see what comes of it since the cabbage has been so persistent.
This is the first time it has flowered. Only sent up one secondary stalk in the second year, and it overwintered before bolting. I’m close to harvesting seed from it, though. Will be interesting to see how the plant responds.
