Plant Profile: Brassica rapa (Pekinensis Group)

The Pekinensis group of Brassica rapa, part of the mustard family, is known by several names that often overlap with those of the Chinensis group. These names include Chinese Cabbage, Celery Cabbage, Napa Cabbage, and Bok Choy. This group is characterized by its broad-leaved, compact heading varieties of Chinese cabbages. The term "Brassica" is derived from Latin, meaning cabbage.

These plants thrive in cooler weather and can withstand light frosts, making them suitable for spring or fall cultivation. They should be planted in fertile, well-drained soil with full sun exposure, and regular watering is essential to maintain soil moisture. Utilizing row covers can help mitigate insect issues. For spring planting, it's advisable to use transplants or start seeds indoors 6-7 weeks prior to the last frost. Alternatively, seeds can be sown directly for a fall harvest. Row covers can also provide protection against cold temperatures.

This variety is known for producing a dense, tall, barrel-shaped head. The leaves grow upright and are pale, thin, and tender. Harvesting can occur once the heads reach a usable size, feeling firm and dense to the touch. If they are not yet firm, they require additional time to mature. It is crucial to harvest promptly once they are ready, as they can quickly lose quality. The emergence of a flower stalk, known as bolting, indicates the cessation of leaf growth and results in a bitter taste.

Common issues include pests such as aphids, whiteflies, flea beetles, and caterpillars like cabbage loopers, cutworms, and beet army worms. Slugs and snails can also pose a threat. Diseases that may affect these plants include club root, white rust, leaf spot, and various rots, including damping off and bacterial soft rot.