What are the precautions for raising vegetable seedlings for late-autumn cultivation?

1. During the day, shade nets need to be used for cover, and ventilation should be strengthened. At noon on sunny days, shade nets still need to be placed over the top of the greenhouse to prevent seedlings from being scorched by strong light. At the same time, pay attention to strengthening ventilation, control the temperature inside the greenhouse well, and strictly prevent high-temperature damage. Generally, during the seedling-raising period for solanaceous vegetables, the daytime temperature inside the greenhouse should be controlled at around 30°C; during the seedling-raising period for cucurbit vegetables, the daytime temperature inside the greenhouse should be controlled at 32°C. When the temperature inside the greenhouse exceeds 35°C, ventilation should be increased.

2. At night, pay attention to keeping the greenhouse warm to avoid cold damage to seedlings from low temperatures. Be sure to close the greenhouse vents tightly in the evening to prevent seedlings from being hit by cold wind at night and growing poorly. During the seedling-raising period for solanaceous vegetables, the nighttime temperature inside the greenhouse should be controlled at 16°C; during the seedling-raising period for cucurbit vegetables, the nighttime temperature inside the greenhouse should be controlled at 12~18°C. If it is lower than this standard, warming measures should be taken promptly.

3. Pay attention to strengthening management during cloudy and rainy days.

1. On cloudy and rainy days, ventilation should be strengthened for vegetables in the seedling-raising period, and watering and spraying pesticides should be avoided as much as possible. When pesticides must be used, dust formulations should be chosen to avoid increasing humidity inside the greenhouse and inducing diseases.

2. Sufficient light should be maintained inside the greenhouse.

3. After a long period of cloudy weather followed by sudden clearing, shade nets should be used promptly to provide shade, so as to prevent vegetable seedlings from "flash wilting."

4. When it rains, the vents on the greenhouse roof should be closed tightly to prevent rainwater from entering and causing vegetable diseases.

4. Pay attention to management during the seedling stage. After emergence, thin the seedlings 1~2 times at the appropriate time, remove diseased and weak seedlings, and keep the seedlings from becoming crowded and leggy. Do not water too much during the seedling stage; keep the soil moist. In autumn, watering should be done in the morning and evening when the soil is cool.

5. Strengthen pest and disease control during the seedling stage. There are many pests and diseases when raising seedlings in autumn, so attention should be paid to pesticide spraying for control. Disease control during the seedling stage: for damping-off and rhizoctonia rot, Heguoli (12.5% diniconazole) can be used at 16 grams per mu, mixed with 30 kg of water, and sprayed for control; for gray mold, prevent it from the seedling stage, and chlorothalonil, dufulin, and procymidone can be used for control. Pest control during the seedling stage: imidacloprid can be used to prevent aphids; for the underground pest mole cricket, insecticides can be mixed into bait to poison and kill them.