Growing cabbage in zone 6b

For spring cabbage in zone 6b, transplants typically go into the ground 3 to 5 weeks before the last frost date, which falls around late April across most of the zone. Starting seeds indoors 6 to 8 weeks before transplant date puts germination in late February to early March. Harvest for early varieties such as Early Jersey Wakefield runs late May through June; heavier storage types like Brunswick reach maturity in late June or early July.

Fall cabbage is started from seed in late June to mid-July, with transplants going out in July or early August. Most varieties need 70 to 100 days from transplant to harvest, so the goal is landing heads at full size in September through mid-October, before the first hard freeze, which arrives in zone 6b roughly mid-October.

The primary adjustments in zone 6b center on the three diseases most likely to affect brassicas here: Downy Mildew, Clubroot, and White Mold. Downy Mildew pressure rises in cool, wet springs and again in fall; adequate plant spacing for airflow and avoiding overhead irrigation reduce incidence. Clubroot is a soil-borne pathogen that persists for years once established; raising soil pH to 7.0 or above and rotating brassicas on a minimum four-year cycle are the practical controls. White Mold develops when canopy moisture stays high through cool, humid stretches.

Stink bug pressure, a noted zone 6b challenge, increases from late summer into fall and coincides directly with the fall cabbage crop. Row covers are the most effective physical barrier through September. No additional winter protection is needed since cabbage in zone 6b is harvested before hard freezes, not overwintered in the field.