Growing cabbage and its friends
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roccoli, cabbage, Brussels sprouts, kale… they are all varieties of the same species, Brassica oleracea. So are cauliflower, collards, kohlrabi and gai lan, also known as Chinese broccoli. Mustard, turnip and bok choy are in the Brassica genus too, but they are not in the species oleracea. Does it matter? Not really, but it’s oleracea were talking about here. Folks started cultivating wild cabbage, perhaps as long ago as 5000 years, and definitely by 2000 BCE. By selecting seed from those with the biggest leaves or stems or flowers, all these different sizes, colours and shapes of vegetable came to be. Cabbages and their ilk can be grown anywhere with good, fertile soil, so long as there are enough frost-free days (or days with just a little frost) for them to reach maturity in the garden. Most like long days but prefer cooler summers and won’t do well when the thermometer goes above 26 degrees Celsius; they tend to bolt. How do they grow them in the hot US South? In fall, not in summer. Although brassicas are cool-season crops, they need warm soil to germinate from seed. The solution a lot of gardeners use for all but kale and collards is to start plants indoors and transplant 24 • 2020
Wild cabbage (above) has been bred into a wide range of cultivars, including broccoli, cabbage, brussel sprouts, kale, cauliflower, collards, kohlrabi and gai lan.
This family of vegetables has a shallow root system, so you need to keep the area weeded. Remove weeds by hand, not by hoe, to avoid damaging the roots. And, of course, keep it mulched. When you plant them out in the early spring, consider a row cover or some other protection. This will keep a number of pests out and keep the temperature more consistent. Water is of great importance. These vegetables like a lot of it and they like the same amount of it from day to day, until they’re getting ready for harvest. Planting cabbage and broccoli for the Issue 4
first time? It’s a good excuse to invest in soaker hoses for watering because brassicas would rather stay dry above their feet. Also important is pH. Brassicas grow best around 6.8 or 7. If you don’t know what your soil pH is, pick up a test at the garden centre. It’ll be a fun experiment. Then amend your soil to suit. And while you’re at it, add plenty of compost because brassicas are heavy feeders. Kale, collards, kohlrabi and gai lan These are the easiest brassicas to grow. You can seed them directly into the soil and harvest in 60 days or less. For kale, collards and gai lan, harvest the leaves as needed, choosing the outer leaves first. Once you cut the innermost leaves the plant may stop producing. For kohlrabi, harvest when the bulb gets to be about the size of a tennis ball. Don’t wait too long because older plants have an unpleasant texture. Broccoli There is a critical point of 10 days while growing broccoli, during which if the heat goes and stays above 35 Celsius for 4 days the broccoli will have badly shaped heads. This critical point is between the vegetative phase, when the plant is gaining size, and the flower bud stage. localgardener.net
