Irrigation: After mid-June, 4 to 5 gallons of drip bucket liquid fertilizer every two to three weeks makes an enormous difference.  You’ll be surprised at the size of the heads and the quality of side shoots.  A fertigated May sowing will be exhausted by October.  Take a chance:  a heavy side-dressing of strong compost or complete organic fertilizer when the rains return may trigger a massive spurt of new, larger heads from buds located below the soil’s surface.

Varieties: Many hybrids have weak roots.  I’d avoid anything that was “held up on a tall stalk” for mechanical harvest or was “compact” or that “didn’t have many side-shoots”.  Go for larger size.  Territorial’s hybrid blend yields big heads for over a month followed by abundant side shoots.  Old, open-pollinated types like Italian Sprouting Calabrese, DeCicco, or Waltham 29 are highly variable, bushy, with rather coarse, large-beaded flowers, second-rate flavor and many, many side shoots.  Irrigating gardeners who can start new plants every four weeks from May through July may prefer hybrids.  Dry gardeners who will want to cut side shoots for as long as possible during summer from large, well-established plants may prefer crude, open-pollinated varieties.  Try both.

Broccoli:  Purple Sprouting and Other Overwintering Types

Spacing: Grow like broccoli, 3 to 4 feet apart.

Sowing date: It is easiest to sow in April or early May, minimally fertigate a somewhat gnarly plant through the summer, push it for size in fall and winter, and then harvest it next March.  With too early a start in spring, some premature flowering may occur in autumn; still, massive blooming will resume again in spring.

Overwintering green Italian types such as ML423 (TSC) will flower in fall if sown before late June.  These sorts are better started in a nursery bed around August 1 and like overwintered cauliflower, transplanted about 2 feet apart when fall rains return, then, pushed for growth with extra fertilizer in fall and winter.

With nearly a whole year to grow before blooming, Purple Sprouting eventually reaches 4 to 5 feet in height and 3 to 4 feet in diameter, and yields hugely.

Irrigation: It is not essential to heavily fertigate Purple Sprouting, though you may G-R-O-W enormous plants for their beauty.  Quality or quantity of spring harvest won’t drop one bit if the plants become a little stunted and gnarly in summer, as long as you fertilize late in September to spur rapid growth during fall and winter.

Root System Vigor in the Cabbage Family

Wild cabbage is a weed and grows like one, able to successfully compete for water against grasses and other herbs.  Remove all competition with a hoe, and allow this weed to totally control all the moisture and nutrients in all the earth its roots can occupy, and it grows hugely and lushly.  Just for fun, I once G-R-E-W one, with tillage, hoeing, and spring fertilization but no irrigation; it ended up 5 feet tall and 6 feet in diameter.