Most of us know that cabbage, broccoli and cauliflower are classified as crucifers, cole crops, or brassicas. So are all of these other vegetables: kale, brussels sprouts, mustard greens, collards, kohlrabi, turnips, rutabagas, radishes, arugula, bok choy, Chinese cabbage, watercress. "Mr. and Mrs. Cabbage" must have been very busy a few centuries ago. Their many offspring have been cultivated all over the world. Humans now grow a huge variety of cole crops. Brassica is a shortened version of their current botanical family name, Brassicaceae. Crucifer is a shortcut for their former family name, Cruciferaceae. The "crucifer" base of that name was a reference to the easily recognized, cross-like, four petaled flower of plants in this family. There are many other members of this family which are not primarily used as human food. Here we'll focus on the edible Brassicas.
Brassicas are classic "spring and fall crops." They all prefer cool soil temperatures. Spring crops usually start as greenhouse-grown transplants. Fall crops can be grown from summer-planted seed. Brassicas are quite hardy to frost. Gardeners in the middle and southern US zones may be able to grow brassicas well into, or even through, the winter. Cold weather growing has the added benefit of near total lack of insect problems.
Brassicas vary as to whether they have tasty leaves, delicious flowerbuds, or savory roots or stems. Each variety of seed has been developed for the best quality in one of those parts. In spring, look for young plants of broccoli, cabbage, and other large crops. Find seed of all those, and other commonly grown choices like radishes, in seed packet displays. Numerous other varieties of brassicas are sold by vendors such as those listed in Dave's Garden Garden Watchdog.
Brassicas like a rich soil with a pH just slightly acidic. Big ones like cabbage, cauliflower, broccolli and collards need plenty of room between plants, and full sun for best growth. If sunlight is at a premium, plant leafy crop brassicas, like kale, mustard, and many of the Asian leafy greens. Keep these plants watered and fed well. They tend to be fast growing or large plants.
The leafy cole crops are easiest to grow: kale, mustard, Asian greens, arugula. Beginning gardeners should have good results with those. Cauliflower and broccolli are said to be finicky, needing detailed care and maybe a bit of luck too. Find specific planting instructions for each variety on seed packets, seed vending websites, and in quality seed catalogs. Also check our Articles for more information on specific vegetables. Your local university extension service can be an excellent resource for home vegetable culture.
Remember your brassica family relationships when planning and caring for the garden. Don't plant any members of this extended family in the same spot year after year. Doing so would foster diseases particular to the clan. Instead, follow a brassica crop with something from an entirely different vegetable family in the next planting. Insects have their family preferences, too. The European Cabbage Butterfly caterpillar feeds on multiple members of this family, not just cabbage. Watch all cole crops for telltale signs of caterpillar activity or insect feeding. And when any insects attack a brassica, be extra watchful for that particular insect on any other brassica in the garden. The cool weather of spring and fall can reduce or stop insect damage.
These vegetables are packed with nutrients, including the possible cancer fighting glucosinolates. Brassicas diversity means they can be used in many different recipes and prepared many ways. Asian, Mediterranean and European cuisines all have their favorite types of brassicas and ways to prepare them. Cold hardy leafy brassicas may produce over a long period in fall and winter. Root crops store well. And remember that all parts of any of these plants are potential food. If the main crop doesn't work out, you can try making use of the leaves of brassica plants.