Detailed Explanation of Standardized Cultivation Techniques for Water Spinach

Water spinach, originally named water convolvulus, also known as rattan vine vegetable, swamp cabbage, tongxin vegetable, heartless vegetable, urn vegetable, hollow-stem vegetable, bamboo-leaf vegetable, and jointed vegetable. It produces white trumpet-shaped flowers, and the center of its stem is hollow, hence the name “water spinach”. It is widely cultivated as a vegetable in rural areas of southern China.

Morphological characteristics of water spinach Water spinach is a trailing plant with a shallow fibrous root system and strong regeneration capacity. The stems are trailing, round and hollow, soft, green or light purple, with a stem diameter of 1-2 cm. The stems have nodes, and each node can produce adventitious roots in addition to axillary buds; the internode length is 3.5-5 cm, with the longest reaching 7 cm. Leaves The cotyledons are opposite and horseshoe-shaped. The true leaves are alternate, with a smooth surface, entire margins, and very pointed tips; the veins are reticulate, the midrib is distinctly raised, and the leaves are lanceolate, long-ovate, or heart-shaped. The leaf width is 8-10 cm, with the widest reaching 14 cm, and the leaf length is 13-17 cm, with the longest reaching 22 cm. The petioles are relatively long, about 12-15 cm, with the longest being 17 cm. Fruit The fruit is hollow and concave, a capsule, nearly round; the seeds are dark brown, with a thousand-grain weight of 32-37 g. Water spinach is propagated by seeds or tender stems, and in the north by seeds. It is a trailing herbaceous plant, smooth all over. There are no tuberous roots underground. The stems are hollow. The leaves are alternate, elliptic-ovate or long-triangular. The flowers are usually white, and may also be purplish red or pink. The seeds have fine hairs. The flowering period is July to September. Standardized cultivation techniques for water spinach

1. Varieties. (1) White-flowered type: leaves are long heart-shaped, stems and leaves are thick and light green, flowers are white, the texture is tender, and the quality is good. Examples include Daguqing and Dajibai. (2) Purple-flowered type: stems and flowers are tinged with light purple, with more fiber and poorer quality, but strong stress resistance. (3) Ji'an large-leaf water convolvulus: suitable for cultivation in loam or clay soil, prefers nitrogen fertilizer, with luxuriant stems and leaves, hollow jointed stems, large leaves, high yield and good quality, and strong adaptability.

2. Site selection: Water spinach is suitable for moist soil rich in humus, with strong branching, well-developed adventitious roots, rapid growth, high planting density, frequent harvesting, high yield, and tolerance to heavy fertilization. Therefore, sunny, fertile fields with a water source should be selected for planting. Cultivation in protected facilities gives even better results.

3. Sowing. Direct seeding in the open field and seedling transplanting are both acceptable, and the sowing period is generally mid-to-late April. For direct seeding in the field, drilling or hill sowing can be used, with a row spacing of 30-35 cm and a hill spacing of 15-20 cm, sowing 3-4 seeds per hill, followed by immediate watering after sowing; seedlings emerge in about 7 days. Dense sowing is also possible, harvesting when the seedlings are 17-20 cm tall. After sowing, cover with plastic film to increase temperature and retain moisture, and remove the film after the seedlings emerge.

4. Planting and management. Water spinach has no strict requirements for soil conditions, and clay loam with low terrain, moist and fertile soil is suitable for cultivation. In the early stage, timely intertillage and loosening of the soil should be carried out to raise the ground temperature. In summer, when the temperature is high and the plants grow quickly, the demand for fertilizer and water is large, so frequent and heavy watering is needed (dry air and insufficient soil moisture can easily lead to increased fiber in water spinach, affecting yield and quality), and topdressing should be combined with watering. In autumn, when the temperature turns cooler, timely intertillage, weeding, and topdressing should be carried out, and attention should be paid to controlling pests such as red spiders. The harvest period of water spinach is long, and generally after each harvest, 10 kg of ammonium sulfate per mu should be applied together with watering.

5. Field management: From the cotyledon stage to the 4-5 leaf seedling stage, the suitable temperature for water spinach is 20-25 degrees C. The suitable temperature for stem and leaf growth is 25-35 degrees C, and it has no strict requirements for light conditions. It has a very large demand for water and fertilizer, so in addition to applying sufficient base fertilizer, large amounts of topdressing are also needed, with 1-2 topdressings after each harvest; the topdressing concentration should be light first and then concentrated, mainly nitrogen fertilizer. Drought and fertilizer deficiency both affect yield and quality. For harvesting water spinach, if it is a one-time harvest, thinning can be done when the plant height is 12-15 cm. If it is harvested multiple times, thinning and pulling for market can be combined with final thinning when the plant height is 18-21 cm, with a plant spacing of 12-15 cm; the remaining seedlings can be harvested multiple times for market, and the first harvest begins when the plant height is 33 cm, leaving two stem nodes at the stem base. For the second harvest, the second node left at the stem base is harvested. For the third harvest, the first stem left at the stem base is harvested, so as to achieve renewed sprouting at the stem base. In this way, the stems and vines harvested afterward can remain thick and strong. Harvesting by pinching with the hands is preferable; if knives or other iron tools are used for cutting, the cut surfaces are prone to rust and death.

6. Pest and disease control: Water spinach has pests such as diamondback moth, red spider, aphids, and leaf roller, which should be controlled in a timely manner. Among diseases, white rust is the most serious and can be controlled by spraying 1:1:200 Bordeaux mixture, preferably with an interval of 10 days each time.

7. Harvesting. Timely harvesting is the key to high yield and good quality in water spinach. In production, it can generally be harvested when the seedlings are 20-30 cm tall. During the first and second harvests, 2-3 nodes should be left at the stem base to facilitate the sprouting of new buds after harvest, promote lateral branch development, and strive for high yield. After 3-4 harvests, the plants should undergo one heavy harvest, that is, leaving only 1-2 nodes at the stem base, to prevent excessive lateral branches from causing weak and slow growth.