Pai Tsai (結球白菜, 大白菜)

Water spinach (空心菜) is a herbaceous perennial aquatic or semi-aquatic upland crops and is also called Water Convolvulus that belongs to the morning glory family (Convolvulaceae).

Other names of water spinach includes; Tropical spinach, Kankon, Weng Cai, Ngung Choi, Ung Tsoi, Ung Choi, Kong Xin Cai, Tong Si Tsai, Toongsintsai, Hung sam choi, Ong tung tso, Ong Choy, Ungtsai, Tung Choy, Kang Kong, Kang Kung, Rau Muong, Swamp Cabbage and Swamp morning glory.

Because of its trailing vine-like stems which are hollow, they are adapted to grow in water due to their floating ability. Their root systems are readily developed from their nodes that could easily contact with the water or directly to the soil. That's why they can easily grow either in water or in soil condition.

Some varieties of Water spinach are the green stem (Ching Quat) and the white stem (Pak Quat), both favors for any soil type in their growth.

The Pak Quat type is semi-upright with white stem, bamboo leaf appearance with yellow-green leaves. This type is tolerant to heat and humid condition. It's fast growing, high yielding, tender and less fibrous.

The Ching Quat type is semi-upright with green stem, broad green leaves and almost the same growth requirement with Pak Quat variety. Both varieties can be harvested 50 days after seed sowing or transplanting.

Swamp cabbage is rich with Iron and Vitamin A.

For more information on growing spinach, refer to http://www.gardenersnet.com/vegetable/spinach.htm