Detailed Explanation of the Key Techniques for Growing Water Spinach in Greenhouses

Water spinach is one of the leafy vegetable varieties that the general public loves to eat. It is produced in larger quantities in summer and autumn. In winter and early spring, due to the lower temperatures, it is not suitable for its growth. However, in recent years, through trial cultivation in small arch sheds, plastic film greenhouses and other facilities, success has been achieved. It can be supplied on the market around the Spring Festival and has achieved relatively good economic benefits. Below, let us take a look together at the greenhouse cultivation techniques for water spinach!

Variety Selection for Water Spinach

Water spinach has two types: seed water spinach and vine water spinach. In the north, seed water spinach, that is, propagation by seed, is mostly used. Generally, the Thai pointed-leaf variety is mainly selected, and local or Guangxi willow-leaf (pointed-leaf) varieties can also be used for cultivation.

Sowing Methods for Water Spinach

1. Seed soaking and germination: The seed coat of water spinach seeds is thick and hard. If sown directly, germination will be slow due to low temperature. If there is prolonged low-temperature rainy weather, it will cause the seeds to rot. Therefore, it is advisable to sow after germination. Soak the seeds in warm water at about 30°C for 18-20 hours, then wrap them in gauze and place them at 30°C for germination. When 50%-60% of the seeds have sprouted, they can be sown.

2. Sowing method: Water spinach can be broadcast sown or drilled sown. The seeding rate per mu is 15-20 kg. After broadcast sowing, cover with fine soil about 1 cm thick. For drilling sowing, dig a shallow furrow 2-3 cm deep across the bed surface every 15 cm, evenly scatter the seeds into the shallow furrows, then cover with fine soil, then cover the bed surface with a shade net, pour water, and uncover the shade net after the seedlings emerge.

Greenhouse Cultivation of Water Spinach

1. Cultivation season: Greenhouse cultivation can basically achieve year-round production and year-round supply. In order to obtain relatively high economic benefits, sowing should be arranged from October to December, with marketing from December to March of the following year.

2. Land preparation and fertilization: Water spinach grows quickly and has strong branching ability, so it needs more fertilizer and water. When planting, sufficient base fertilizer should be applied. Generally, 1500-2000 kg of decomposed organic fertilizer and 100 kg of plant ash are applied per mu, fully mixed with the soil, and raised into beds 20 cm high and 130-150 cm wide (including ditches).

Greenhouse Management of Water Spinach

1. Temperature and humidity management: During greenhouse cultivation in winter, the temperature is low, the humidity is high, and the duration of continuous low-temperature rainy weather is long, which is extremely unfavorable to the growth of water spinach, which likes warmth. Therefore, heat preservation and cold protection are the key to off-season cultivation of water spinach. After sowing, when there is sufficient sunlight and the temperature is relatively high, ventilation should be strengthened to remove moisture, and try to avoid the temperature inside the greenhouse being higher than 35°C, so as to prevent the plants from developing diseases, maintain vigorous growth, and increase yield. If low-temperature weather occurs after sowing, the greenhouse should be sealed in time, and the temperature inside the greenhouse should be maintained above 10°C, otherwise it will cause freezing damage. The relative air humidity inside the greenhouse may reach 100% at relatively high temperatures and on rainy days. At this time, the films at both ends or around the greenhouse must be opened in time for ventilation.

2. Fertilizer and water management: Water spinach is a crop harvested multiple times. Therefore, in addition to applying sufficient base fertilizer, multiple topdressings must be carried out to obtain high yield. During the seedling stage, 10%-15% dilute human manure and urine can be used for drenching, using 1000-1500 kg per mu. When the seedlings have 3-4 true leaves, apply a mixture of 15-20 kg of compound fertilizer and 2-4 kg of urea. During the harvest period, topdress once after each harvest, applying 5-8 kg of compound fertilizer per mu. Water spinach has a relatively large water requirement, so it should be watered frequently to keep the bed surface moist.

3. Pest and disease control: The main diseases of greenhouse-cultivated water spinach include damping-off and stem rot during the seedling stage, which are caused by low temperature and excessive relative humidity. Reducing humidity can alleviate the occurrence of the diseases. At the same time, 700 times Ridomil or 800 times Kameitong can be sprayed for control. Its main insect pests include mites and red spiders, which can be controlled with 1000 times Komite or 1500 times Cascade.

4. Timely harvesting: Generally 35-45 days after sowing, when the water spinach plants grow to 35 cm tall, they should be harvested in time.