A Detailed Guide to Greenhouse Cultivation Techniques and the Best Sowing Times for A-choy
A-choy is a pointed-leaf type leaf lettuce harvested for its tender shoots and tender leaves, with a delicate texture that is deeply loved by the public. So what are the cultivation techniques for A-choy? How do you grow it in a greenhouse? When is the best time to sow?
1. Growth habits of A-choy
A-choy seeds are not demanding when it comes to germination conditions; generally, they can germinate smoothly at above 4°C. If the temperature is between 15 and 20°C, A-choy seeds need only 3 to 4 days to germinate. If the temperature exceeds 30°C, A-choy seeds will not germinate. The most suitable temperature for the A-choy seedling stage is 12 to 20°C. If the daytime temperature exceeds 24°C and the nighttime temperature is also above 19°C, it can easily cause premature bolting in A-choy.
2. What are the greenhouse cultivation techniques for A-choy? When should you sow?
1. Sowing time
(1) For spring sowing from January to March, raise seedlings inside the greenhouse. Build 2 beds in a standard greenhouse with 1 ditch in the middle, deep-plow and build the beds, water thoroughly to soak the base, scatter the seeds over the beds, cover with seed soil just enough to cover the seeds, and lay plastic film flat over them. Seedlings generally emerge in 10 to 15 days; in rainy and low-temperature periods, emergence takes a bit longer. After the seedlings emerge uniformly, remove the plastic film and ventilate. During the day, guard against high temperatures damaging the seedlings; at night, guard against cold damage.
(2) For summer sowing from April to June, raise seedlings in the open field. Choose high ground, 2 m including ditches, deep-plow and apply decomposed barnyard manure, then build and level the beds. Soak the seeds for 3 hours and sow after the seeds are air-dried. Water the seedling bed thoroughly to soak the base, scatter the seeds over the bed surface, cover well with seed soil, and water thoroughly. In case of high temperature and drought, cover the beds with shade netting, and uncover the netting in the morning and evening after the seedlings emerge uniformly. Fertilizer and water in the seedling bed should be moderate; it should not be too dry.
(3) For autumn sowing from July to September, raise seedlings inside the greenhouse. A-choy seedling raising requires seed soaking and germination promotion. The method is to wrap the seeds in gauze, soak them in water for 3 to 4 hours, then take them out and place them in the refrigerator's cold storage compartment for 10 to 15 hours. Once 75% have sprouted, they can be sown. For autumn sowing and seedling raising, it is best to use a small arched shed or greenhouse. After emergence, pay attention to soil moisture; it should not be too dry or too wet, and weeds should be removed promptly to ensure smooth drainage.
2. Seedling stage management
When A-choy seedlings grow two true leaves, divide the seedlings, with a transplanting density of 6×6 cm. The A-choy seedling bed should be kept moist, and shade is needed at noon. At the same time, during the seedling stage of A-choy, attention should be paid to pest and disease control.
3. Land preparation and bed building
Before planting A-choy, apply 3500 to 4000 kg of decomposed organic fertilizer, 20 to 25 kg of phosphate fertilizer, 40 to 50 kg of nitrogen fertilizer, and 10 to 15 kg of potassium fertilizer per mu. The bed width is 1 to 1.5 m, the plant and row spacing is 10×10 to 15 cm, and 40,000 to 50,000 plants are planted per mu.
4. Intertillage and weeding
After A-choy is planted and has recovered from transplanting, apply 1 to 2 small amounts of quick-acting nitrogen fertilizer along with watering, generally 5 kg of urea or ammonium sulfate per mu, to promote plant growth and tillering. After that, keep the soil moist frequently and carry out intertillage and weeding in a timely manner.
5. Cover the greenhouse at the right time
A-choy is a fast-growing leafy vegetable, and its suitable growth temperature is 18 to 25°C. When the nighttime temperature is below 12°C, the greenhouse should be covered. After covering, adjust the greenhouse temperature and relative humidity in the greenhouse in a timely manner. Generally, the relative temperature inside the greenhouse should be less than 90%.
6. Rational topdressing
During A-choy cultivation, cleanliness and hygiene should be maintained. In the early and middle growth stages, use 0.3% potassium dihydrogen phosphate and urea solution for foliar spraying 3 to 4 times. Apply topdressing 2 to 3 times throughout the growth period, with 5 to 10 kg of urea or 10 kg of ammonium sulfate per mu.
7. Pest and disease control
The main insect pest of A-choy is aphids, which can be sprayed with 800-fold dilution of 40% dimethoate emulsifiable concentrate. The main diseases are downy mildew and soft rot, which can be controlled by spraying 300 to 500-fold dilution of 70% mancozeb wettable powder and 0.02% agricultural streptomycin, respectively.
8. Harvest at the right time
When A-choy has 30 to 34 leaves, a plant height of 45 to 48 cm, and a spread of 60 to 69 cm, it can be harvested all at once at 2 to 3 cm above the ground. After harvesting, remove old leaves and diseased leaves and supply them promptly to the winter market.
This is exactly the good season for growing A-choy in greenhouses, so farmers who are interested should hurry up!