What are the cultivation techniques for New Zealand spinach? A detailed guide

New Zealand spinach (Tetragonia expansa Murr.), also known as New Zealand spinach or sea spinach, is an annual or perennial trailing herbaceous plant of the genus Tetragonia in the family Aizoaceae. It originated in Australia, New Zealand, Chile, Southeast Asia and other places, and is mainly distributed in the tropics. Europe, America, Indonesia, India and other countries have long cultivated it as a vegetable. It has been introduced into China for 200 years, but it is not widely grown and little known. New Zealand spinach has strong stress resistance, grows vigorously, and its tender stems and leaves are tender and delicately fragrant. It is easy to cultivate and rarely suffers from pests and diseases, making it a pollution-free green vegetable that requires no pesticide spraying; under protected cultivation conditions, year-round cultivation can be achieved in all parts of China.

1 Characteristics and traits

New Zealand spinach has a well-developed root system, with strong drought tolerance and poor waterlogging tolerance. The stem is round and semi-trailing; it grows upright at first and later creeps along the ground, with strong branching ability, and lateral branches can grow from every leaf axil. The leaves are alternate, roughly triangular in shape, with entire margins, thick and fleshy, and dark green. The flowers are relatively small and yellow, borne in the leaf axils. The seeds are dark brown, with ridges on the surface and fine spines at the tips of the ridges, with a 1000-seed weight of 80-100 g.

2 Requirements for environmental conditions

2.1 Temperature New Zealand spinach prefers a warm, humid climate and is highly adaptable, tolerating both heat and cold, but its aboveground parts are not frost-tolerant. Seeds can germinate at 8-30°C, with an optimum germination temperature of 25-28°C; the optimum temperature for seedling growth is 20-25°C, and it can still grow normally under high summer temperatures. It can tolerate low temperatures of 2-3°C for short periods. In warmer regions it can overwinter safely in the open field and become a perennial plant.

2.2 Humidity New Zealand spinach prefers a moist soil environment. It has strong drought tolerance but is not tolerant of waterlogging. Moist soil conditions are favorable for its growth and development, and during the seedling stage the soil should be kept in a state of alternating dryness and moisture. The water requirement is uniform throughout the entire cultivation process. New Zealand spinach plants are relatively drought-resistant, but in production, excessive drought will seriously affect their growth and development, thereby reducing yield and quality.

2.3 Light It has no strict requirements for light conditions and is relatively shade-tolerant, growing well under both weak and strong light. Providing sufficient light during the seedling stage is favorable for the formation of strong seedlings.

2.4 Soil and fertilizer It prefers fertile loam or sandy loam, is relatively salt-alkali tolerant, and has a relatively high demand for nitrogen and potassium fertilizers. For cultivation, fertile, loose and moist soil is best. During the seedling stage, attention should be paid to the rational application of nitrogen, phosphorus and potassium fertilizers.

3 Nutritional and medicinal value

According to measurements, every 100 g of the edible portion contains: protein 1.5 g, fat 0.2 g, carbohydrates 0.6 g, calcium 58 mg, phosphorus 28 mg, iron 0.8 mg, vitamin A 4400 international units, vitamin C 30 mg, vitamin B1 0.04 mg, vitamin B2 0.13 mg, vitamin B5 0.5 mg. Pharmacological studies have shown that the whole plant of New Zealand spinach can be used as medicine. It is sweet in taste, slightly pungent, and neutral in nature, and has effects such as clearing heat and detoxifying, promoting diuresis and reducing swelling. Regular consumption of New Zealand spinach has a good effect on relieving pain in patients with enteritis, septicemia, kidney disease and other conditions. It can treat red and swollen sores, red eyes caused by wind-heat, and neutralize snake venom, and it also has anticancer effects.

4 Methods of consumption

The tender stem tips and tender leaves of New Zealand spinach are edible. They can be stir-fried or blanched in boiling water, cooled, and mixed with seasonings to make a cold dish; the color is emerald green, the texture is tender and smooth, and the flavor is delicately fragrant. They can also be combined with eggs to make New Zealand spinach egg-drop soup, or cooked with japonica rice to make New Zealand spinach porridge, which has effects such as strengthening the spleen and stomach, dispelling wind and reducing swelling, and relieving diarrhea and dysentery.

5 Cultivation techniques

5.1 Cultivation season Open-field cultivation can be carried out during the frost-free period, sowing when the soil temperature stabilizes at 10°C. Plastic tunnels can achieve early and delayed cultivation, and solar greenhouses can achieve four-season cultivation. For seedling raising and transplanting, seedlings can be raised in a greenhouse 40-50 days before the local late frost period, and transplanted to the field after the late frost. In view of the difficult water absorption of New Zealand spinach seeds, the long germination period, and uneven emergence, production mostly adopts the method of raising seedlings in a greenhouse and transplanting.

5.2 Seedling raising

5.2.1 Seedbed preparation Clean up the residues of the previous crop and weeds, plow and sun-dry the soil, and make a seedling bed 1.2 m wide. Apply 8-10 kg of screened decomposed organic fertilizer per square meter. Shallowly cultivate the bed surface with a hoe, mix the seedbed soil and fertilizer evenly, and level it with a rake before sowing.

5.2.2 Seed treatment New Zealand spinach is propagated by fruit. The fruit skin is relatively hard and thick, making water absorption relatively difficult. Without treatment, the germination period lasts as long as 15-80 days, so the seeds need to be treated before sowing. There are 2 treatment methods: ① Warm water soaking method: soak the seeds in warm water at about 55°C for 24 hours, then germinate them; ② Mechanical treatment: grind coarse sand together with the seeds to cause mechanical damage to the seed coat, increase the permeability of the seed coat, then soak in clean water for 12 hours, and then germinate them, which is favorable for seed germination.

5.2.3 Germination and sowing For the treated seeds, drain the water from the seed surface, wrap them in a clean wet towel or gauze, and place them under conditions of 25-28°C for germination. Rinse the seeds with warm water once a day. When 80% of the seeds have sprouted, they can be sown. Before sowing, water the seedling bed thoroughly, sow the seeds in the bed at a spacing of 6-8 cm square, cover with 1 cm of screened fine soil, and cover the bed surface with a layer of plastic film to help preserve heat and moisture. When 50% of the seeds have pushed through the soil, remove the plastic film. Each mu requires 0.75-1 kg of seeds.

5.3 Management after sowing After sowing, maintain the room temperature at about 25°C during the day and above 15°C at night. After the seedlings emerge uniformly, cover again with 0.5 cm of screened fine soil to fill cracks and preserve moisture, while lowering the indoor temperature, keeping the daytime temperature at 20-22°C and the nighttime temperature at 12-15°C. Before transplanting, lower the temperature appropriately to harden the seedlings, keeping the daytime temperature at about 20°C and the nighttime temperature above 10°C. Seedlings grow slowly, so try not to water them. When the seedlings have grown 5-6 true leaves, appropriately restrain their growth and cut them into blocks for transplanting.

5.4 Transplanting New Zealand spinach has a long growth period, so sufficient base fertilizer should be applied before transplanting. Generally, apply 5000 kg of decomposed organic fertilizer and 20 kg of quick-acting nitrogen fertilizer per mu (666.7 square meters). Deeply plow, harrow finely, and level the soil, then make a flat bed 1.5 m wide. Transplant at a plant spacing of 30 × 50 cm and row spacing, watering as you transplant. The transplanting water should not be too much, so as to help the seedlings recover and start growing early.

5.5 Field management New Zealand spinach has a long growth period and is planted once and harvested many times, until the first frost. During the growing period, it requires relatively large amounts of nitrogen and potassium fertilizers. In addition to applying sufficient base fertilizer before transplanting, topdressing should also be carried out multiple times to increase yield. Generally, from transplanting to harvest, appropriate amounts of urea and potassium chloride should be applied according to growth vigor. Before each harvest, apply 10-15 kg of urea, 5-10 kg of potassium chloride, or 1500 kg of decomposed human manure and urine per mu, flushed in with water. New Zealand spinach is harvested for its tender stems and leaves. When water is lacking, the leaves become hard, so it should be watered frequently during the growing period to keep the soil alternately dry and moist. In the rainy season, drain water in time to prevent waterlogging and avoid root rot. In the early stage, pay attention to intertillage and weeding. After the plants close rows, pull weeds at any time and avoid intertillage. New Zealand spinach has strong resistance to pests and diseases, and generally few pests and diseases occur. Occasionally, some leaf-eating pests gnaw on the leaves, which can be controlled by spraying with a 1000-fold solution of 90% trichlorfon crystals.

5.6 Harvest When the plants grow to 20-30 cm, harvest the tender stems and leaves in time. During the growth process of New Zealand spinach, flower buds form in almost every leaf axil. When harvesting, remove the flower buds and cut off thin and weak branches, keeping thick and strong new branches to ensure vegetative growth and promote sturdy plants and enlarged leaves. If harvesting is too late, not only will the leaves age and coarse fiber increase, affecting quality, but the leaves will also turn yellow and lose their nutritional value. Generally, harvest once every 5-7 days, and continuous harvesting can last 5-6 months. After harvesting, bring to market in time. The yield per mu is 3000-5000 kg.