January 9, 1998
I chose a rather misleading title for this article, since kale is a much overlooked vegetable. I'm not really sure why. Perhaps people have purchased it at the store, and decided they didn't like it. Or maybe they've tried eating leaves from ornamental kale. Whatever the reason, I've had folks who've never grown kale tell me they hate the stuff!
But kale seems to be making a comeback. I'd guess this is largely due to people becoming more health-conscious; after all, kale is reputed to contain more vitamins and minerals, per serving, than any other garden vegetable. It is my hope, though, that people will learn to like it, not just tolerate it.
Kale is a member of the important Brassica genus in the family Crucifereae. Scotch types are B. oleracea acephala, while Red Russian varieties fall under B. napus pabularia. Since plants within a species will usually readily cross, this means Scotch kales can cross with plants like broccoli, cauliflower, and cabbage (any Brassica oleracea, in other words), while Red Russian kale only needs to be isolated from rutabagas. Of course this doesn't really matter to you unless you are planning on saving seed from these plants!
Kale seeds tend to be vigorous sprouters, and rival radishes in the speed at which they spring from the ground. Ample nitrogen should be provided early in the plant's life to promote rapid large growth. But, to encourage maximum cold hardiness, nitrogen should not be provided in the later stages of growth. I like to mix ¼ cup of cottonseed meal into the soil around the spot where I'm planting the seeds – that seems to be plenty of nitrogen for these robust plants' lifetime. All salad kales are large plants, and should be given a minimum of 18 inches in each direction to reach their mature size.
Like the other Brassicas, kale's leaves become much sweeter after experiencing a good frost. This is part of their survival mechanism. By pumping sugar into the water inside the leaves, these plants lower the temperature at which freezing begins. This is why kale really shouldn't be grown as a spring or summer vegetable – it tastes pretty bad if it hasn't been frosted, and doesn't compete well with lettuce and spinach in their prime.
In the winter garden, though, kale is unrivaled. There are other equally hardy greens like mache and minutina, but these are shrinking violets in comparison. The salad kales are absolutely stunning plants! Even the most discriminating ornamental gardener should be pleased with them as part of an edible landscape. As a matter of fact, I prefer them to their ornamental cousins in appearance; and certainly there's no competition when it comes to taste!
To grow kale for fall or winter, try sowing the seed two or three months before your area's average first frost date. Here in western Washington state I get it started during the first half of July. Since kale is so vigorous, there isn't much reason to raise transplants; directly sow it in the garden instead.
You can count on kale to be hardy to at least 5F; and some varieties will take much colder temperatures, especially if given the small amount of protection provided by a floating row cover. Kale is not bothered by rain at all, and will happily thrive through one of my region's fabled soggy winters.
Web pages about kale
More information on kale is available from Oregon State University. Territorial Seed Company is a good source for kale seed, and their cultural information is very helpful. Or perhaps you'd like to try a recipe for kale and potato soup, Mame's steamed kale, or Kale creamed pasta sauce? Boy that last one sounds good to me!
All contents © Travis Saling
This page was last updated July 9, 2011