What are the current key management priorities for greenhouse vegetables?
The autumn-winter greenhouse vegetables currently being grown are in the peak fruit harvest period, while the winter-spring greenhouse vegetables are in the seedling growth and flowering stages, making this a critical period for field management. The technical priorities for their management are briefly described below:
1. Adjust to suitable growth environment conditions. Temperature, light and air humidity are important environmental conditions for vegetable growth and development. Temperatures now change frequently, with large day-night temperature differences, so the indoor temperature must be adjusted promptly by opening and closing vents as the outside temperature changes. Warmth-loving vegetables such as tomatoes have a suitable temperature of 23°C to 28°C during the day and 15°C to 18°C at night; cool-loving vegetables such as celery have a suitable daytime temperature of 20°C to 22°C and 10°C to 12°C at night. Light-loving vegetables such as tomatoes and cucumbers must have a greenhouse film light transmittance above 60%, and it is best to replace it with new film that has anti-drip and anti-fog functions, moving the old film that can still be used to greenhouses for sweet (hot) peppers or leafy vegetables. Adjust different indoor relative humidity according to different vegetables. Tomatoes and eggplants are suited to a relatively dry environment, with relative humidity controlled at about 50%; sweet (hot) peppers, cucumbers and leafy vegetables prefer humid conditions, with relative humidity controlled at 70%. Indoor humidity can be adjusted by venting and watering.
2. Scientific watering and topdressing. Newly transplanted greenhouse vegetables should undergo seedling hardening for 10 to 15 days after transplant recovery, controlling watering to promote root growth and downward penetration, and watering and topdressing should begin only when the young fruit has set and starts to swell. Greenhouse vegetable fruits grow rapidly and leaf transpiration is high, so watering and topdressing must be done reasonably according to the weather, soil moisture and plant growth conditions, preferably by applying fully nutritious, properly ratioed instant fertilizer through drip irrigation. Spray fertilizer on the leaves once every 7 to 10 days to quickly supplement the nutrients needed for growth.
3. Do a good job of pruning and removing side shoots, thinning flowers and fruits. Remove old leaves, yellow leaves and side branches from the plants in a timely manner, and thin out excessive and deformed fruits.
4. Do a good job of pest and disease control. Focus on controlling tomato yellow leaf curl virus disease and late blight, cucumber downy mildew, and pests such as whitefly, red spider mite and tea yellow mite. Tomato late blight and cucumber downy mildew are most likely to occur under low-temperature, high-humidity growing conditions, so this environment should be avoided in cultivation management, and vents should be closed promptly on rainy days.
5. Harvest in a timely manner. Timely harvesting can both increase the marketable rate and prevent fruits from weighing down the plant and affecting continued fruiting. Handle fruits gently during harvest to avoid damaging them, and sort and package them for sale according to different specifications.
Liu Zhenghua, Wangdu County Agriculture and Animal Husbandry Bureau