In my quest for f3s of San Michele x Red Rock mammoth, I have learned many interesting things about Brassica oleracea survival and propagation. One of my goals is to produce well adapted crops, which includes being able to produce seed with relatively easy cultivation techniques in this geographical area. You can cellar cabbage but I try to overwinter outside. Usually this requires some sort of protection and the head does not normally survive but varying degress of the rest of the plant can. With just an intact stem, they usually go on to flower. This year, I have trenched my cabbage outdoors (without the heads). As an insurance policy, I also take cuttings.
These are then stored and grown inside. They root relatively easy though I do not get a 100% strike rate, more like 70%. I've managed to get green leafy growth from everything from roots (yes really) and any bit of stem material including relatively small side shoots.
I normally pack them together until I can tell which ones are going to root then I pot up individually. The first time I did this they flowered inside for me despite me preferring that they hang out in vegetative growth until spring. I can see this being useful for doing controlled crosses. I had to hand pollinate these small plants and consequently got only a handful of seeds. I'm hoping with these cuttings that I can do keep them in vegetative growth longer but we shall see as I did harvest these cuttings after fall cold had set in so it is likely they will be vernalized.
This has been a favourite project of mine because the cross tastes great, is hardy but also because I have had so much fun learning what this plant can do.
I'm happy to see the resurgence of interest in Crambe maritima, Seakale, especially among folks interested in perennial vegetables. This forgotten vegetable may have fallen off of the dinner table for many years but I have references to it being grown in Ottawa in the 70s and 80s and it has been growing at the Experimental Farm in downtown Ottawa as an ornamental for years. They have a very impressive patch for those keen on having a gander.
Seakale was traditional foraged for its spring shoots that were naturally blanched by sand (Stephen Barstow, page 5, Around the World in 80 Plants) and eventually made their way into gardens. They are remarkably hardy considering their origins, surviving in my sheltered Canadian Z. 4b sandy garden with dieback only on the coldest years. I started with two varieties: a purple unselected species and Lilywhite, the most common vegetable variety grown.
My collection has grown. I was gifted Angers from a fellow Canadian edible plant enthusiast and now have a swath of seed grown ones. Once a good variety is grown, they can be easily propagated by root cuttings called thongs. So why do I persist with growing out seeds?
When you look up varieties of seakale, you will bump into names like "Pink Tipped." Trying to locate these varieties will give you less result. It is possible that some of these are grown in a garden somewhere (if that's yours, please contact me) but they may have disappeared.
Instead of just crying over lost varieties, why not go back to the beginning: the seed.
In 2013, I started gathering seeds from whatever sources I could find. 2014 and 2015, I grew them out. Here are some of the more interesting results. My goal is to look for interesting leaf form and colour while maintaining good eating qualities and vitality. I would also like to expand the vegetable varieties to include ones good for seakale-broccolis and perhaps even those that have better leaf texture and flavour.
Seakale selection 2015 in pictures
I tend to remove seeds from pods and soak for a few hours first but they can be planted pods and all.
Variation is evident from the seed up through cotyledon to seedling stage. Here are two with very different colouring.
Less vigorous and more vigorous one with purple-blue coloration
Interesting leaf and colour forms. Note the summer heat washes out colour somewhat.
Two by two in the seakale row. Lilywhite on the left versus some species selected as seedlings for purple coloration.
Going dormant in fall, variation in bud colour. Species tend to have purple growth tips whereas Lilywhite has green. Here is a rose growing tip on the left and lavender/green growing tip on right.
Goals for 2016
1. Test for winter hardiness over 2015-2016.
2. Taste shoots, buds and leaves.
3. Do minimal root thong propagation on most interesting varieties and check vigour.
Oxalis tuberosa is an Andean tuber that tuberizes in short days, prefers moderate temperatures and adequate inputs (water, fertility) and is frost intolerant. Its nutritional, taste, cooking and storage (and lets face it aesthetic) qualities make it an interesting crop for development however its goldilocks personality means it grows well in limited regions in North America. I have been participating in several breeding projects to produce more widely adapted varieties from true seed. Some progress has been made in quick to bulk vareities but not sufficient for most potential growers.
Growing for me is not merely about variety + geography. Crops are grown in a cultivation system. If us northerners didn't pre-start tomatoes, we'd probably still get fruit (just ask people with volunteer tomatoes) but we might be disappointed by yields or at least start of fruit set. Planting out sweet potato tubers rather than slipping has lead to crowded growth and significantly lower yield in my experience. Therefore, I'm seeing a potential not only in developing day nuetral crops but also in a selecting for an alternate cropping system for propagation or the plate, especially in adverse years.
In the Ottawa region, even though I protect with floating row cover or even heavier protection depending on the year, I have to harvest in November as the ground freezes shortly thereafter. I therefore, usually pull my plants with intact stems and even foliage, remove large tubers and then store in plastic bags someplace above freezing that is not too dry. I find that any remaining stolons plump up and aerial tubers are produced. This year, I also took stem cuttings for an indoor flowering experiment though I expected that it was likely that I would see mostly just stem to tuber conversion. This is indeed what I saw though in some cases they went from stem to tuber to roots from the tuber to presumedly vegetative growth out of the tuber.
In other cases, I did see some root development off of hte stem though no new vegetative growth (yet). This got me thinking. All stems are potential tubers and stems was one thing I was capable of growing.
Not all of my stored oca readily produce this stem to tuber conversion or at least not in my storage regime. I have not really looked into if there is a correlation to general readiness to produce tubers though infamous Seedling 12 that produced masses of green growth at harvest but zero tubers has finally begun to heavily stem tuberize. Good thing as it sure didn't do the stolonization thing. I was ready to chuck it. Might still do...
Looking at the above plants, you can see the massive potential for propagation material. On the left is a plant that is heavily converting stems to tubers though these would be classified as marbles according to the Guild of Oca Breeders sizing key. On the right, you have stolons that produced tubers or had very small tubers enlarge to a more reasonable size.
Some plants did not do much after harvest in terms of stem->tuber conversion in the near cellar like conditions that they were stored. Seedling 5 on the right was one such though it was a heavy cropper at harvest (comparatively in the Algonquin Student Cultivariable grow out) and its stem cuttings readily tuberized in warmer conditions.
I can see potential in two ways.
The first is that if you are about to lose Oca because of unusual weather or rodent activity but have intact stems and are a small scale enough grower that pulling and storing all your plants doesn't sound too daunting, then this is a potential method to produce propagation material. Alternatively, if you have intact stems and just want more material to share around, you can produce marble or larger sized tubers this way. Note smaller tubers need more care in storage as they are more likely to rot or shrivel up.
Alternate Cropping System
This is more of a pie in the sky idea but I'd like to experiment with it next year. By selecting plants that readily make large tubers in storage, you could develop a system that would work for northern growers. At least until that magical day where we find the day nuetral or super early variety.
All about growing, selecting and using edible plants in the Ottawa valley.