As this highly moldable family is inbred and shaped into more and more exaggerated forms, it weakens and loses the ability to forage.  Kale retains the most wild aggressiveness, Chinese cabbage perhaps the least.  Here, in approximately correct order, is shown the declining root vigor and general adaptation to moisture stress of cabbage family vegetables.  The table shows the most vigorous at the top, declining as it goes down.

Adapted to dry gardening Not vigorous enough

Kale Italian broccoli (some varieties)
Brussels sprouts (late types) Cabbage (regular market types)
Late savoy cabbage Brussels sprouts (early types)
Giant “field-type” kohlrabi Small “market-garden” kohlrabi
Mid-season savoy cabbage Cauliflower (regular, annual)
Rutabaga Turnips and radishes
Italian Broccoli (some varieties) Chinese cabbage
Brussels Sprouts

Sowing date: If the plants are a foot tall before the soil starts drying down, their roots will be over a foot deep; the plants will then grow hugely with a bit of fertigation.  At Elkton I dry garden Brussels sprouts by sowing late April to early May.  Started this soon, even late-maturing varieties may begin forming sprouts by September.  Though premature bottom sprouts will “blow up” and become aphid damaged, more, higher-quality sprouts will continue to form farther up the stalk during autumn and winter.

Spacing:  Make each spot about 4 feet apart.

Irrigation: Without any added moisture, the plants will become stunted but will survive all summer.  Side-dressing manure or fertilizer late in September (or sooner if the rains come sooner) will provoke very rapid autumn growth and a surprisingly large yield from plants that looked stress out in August.  If increasingly larger amounts of fertigation can be provided every two to three weeks, the lush Brussels sprouts plants can become 4 feet in diameter and 4 feet tall by October and yield enormously.

Varieties:  Use late European hybrid types.  At Elkton, where winters are a little milder than in the Willamette, Lunet (TSC) has the finest eating qualities.  Were I farther north I’d grow hardier types like Stabolite (TSC) or Fortress (TSC).  Early types are not suitable to growing with insufficient irrigation or frequent spraying to fight off aphids.

Cabbage

Forget those delicate, green supermarket cabbages unless you have unlimited amounts of water.  But easiest-to-grow savoy types will do surprisingly well with surprisingly little support.  Besides, savoys are the best salad material.

Sowing date: I suggest three sowing times:  the first, a succession of early, midseason, and late savoys made in mid-March for harvest during summer; the second, late and very late varieties started late April to early May for harvest during fall and winter; the last, a nursery bed of overwintered sorts sown late in August.