Info Source: http://www.hort.purdue.edu/newcrop/proceedings1996/v3-488.html#Fig.%206
Chinese broccoli or gai-lan (Brassica oleracea L. var. alboglabra Bailey)
This excellently flavored broccoli relative is also called Chinese kale or kailan. The edible vegetable consists of a tender green flower stem with buds of what will become white flowers. The leaves and stems are light to medium green in color and are covered with a white haze due to cuticle and wax development (Larkcom 1991).
Different varieties of gai-lan vary in stem length and color from light to medium green. About 55-70 days are required from a fall seeding to harvest maturity. It grows best during cooler weather. Gai-lan is planted with 2 to 4 rows per bed, 8 to 12 cm between plants, with a planting density of 108,000 to 220,000 plants/ha. Average seasonal yield, with 2 to 3 harvests, is 320-600 18 kg-crates/ha (Shuler 1995).
At harvest the flower buds should be closed (Fig. 7). After harvest the stem becomes tougher than does that of Chinese kale and it may be peeled before use much as broccoli stems are. Gai-lan, like broccoli, is very perishable. Postharvest defects and recommended conditions are described in Table 2, 3, 4.
Chinese flowering cabbages or choy sums (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee = B. campestris ssp. chinensis var. parachinensis L.H. Bailey)
Choy sums are also referred to as mock pak choy. This vegetable is grown and harvested similar to gai-lan. The white to light green stems are cooked without peeling and have a pleasant, mild flavor. Important quality characteristics are a tender stalk and closed yellow flower buds. For optimum quality, cooler growing weather is required. Under Florida conditions, average days from fall seeding to harvest maturity are 60-70. Choy sum is planted with 3-4 rows per bed with plants spaced 20-30 cm apart; planting density varies from 72,000 to 108,000 plants/ha. Average seasonal yield, with 2 to 3 harvests, is about 620-980 18 kg-cartons/ha (Shuler 1995). Postharvest requirements are similar to those of other cool season leafy vegetables (Table 3 and 4).