Key Management Techniques for Greenhouse Cultivation of Zucchini
Zucchini, also known as eggplant melon, bear (male) melon, white melon, wo melon, small melon, fan melon, horn melon, xun melon, etc. Zucchini is an annual trailing herbaceous plant, with three major strain types: dwarf, semi-trailing, and trailing. Most varieties have obvious main vine dominance. Zucchini contains relatively high amounts of vitamin C, glucose, and other nutrients, with an especially high calcium content. The nutrient content per 100g of edible portion (fresh weight) of different varieties is as follows: protein 0.6-0.9g, fat 0.1-0.2g, cellulose 0.8-0.9g, carbohydrates 2.5-3.3g, carotene 20-40 micrograms, vitamin C 2.5-9 mg, calcium 22-29 mg. Both the elderly and children enjoy eating it.
Growth Habits of Zucchini
Temperature: Among cucurbit vegetables, it is relatively cold-tolerant but not heat-tolerant. The most suitable temperature during the growing period is 20-25°C; growth slows below 15°C and stops below 8°C. Above 30°C, growth slows and diseases are highly prone to occur. The suitable temperature for seed germination is 25-30°C; seeds can germinate at 13°C but very slowly; germination is fastest at 30-35°C but tends to cause leggy growth. The flowering and fruiting period requires higher temperatures, generally maintained at 22-25°C for best results. Early-maturing varieties have stronger low-temperature tolerance. The minimum temperature for root elongation is 6°C, and the minimum temperature for root hair formation is 12°C. At a night temperature of 8-10°C, fertilized fruits can develop normally.
Light: Moderate light intensity is required; it is relatively tolerant of weak light, but insufficient light tends to cause leggy growth. In terms of photoperiod, it is a short-day plant; long-day conditions favor stem and leaf growth, while short-day conditions lead to earlier fruiting.
Humidity: It prefers moisture and is not drought-tolerant, especially during the fruiting period when the soil should be kept moist to achieve high yields. Under high-temperature and drought conditions, viral diseases are prone to occur; however, high temperature and high humidity also easily cause powdery mildew.
Soil: It has no strict requirements for soil; sandy soil, loam, and clay can all be used for cultivation, but deep loam soil easily achieves high yields.
Pollination and Fruit Setting: Zucchini is a crop with separate male and female flowers, and under greenhouse cultivation conditions, artificial pollination is required. 1. Pollination should be carried out between 9-10 AM each day. When pollinating, pick male flowers that opened on the same day, remove the corolla, and gently dab the stamens of the male flower onto the stigma of the female flower to transfer pollen. Each male flower can pollinate 5 female flowers. 2. Use Xiaotianshi foliar spray, which can replace manual flower dipping and fruit smearing, is safe and unaffected by temperature. Currently, the main domestic manufacturer is Nangong Huayang Chemical.
Fertilizer Requirement: It has a relatively high fertilizer requirement. To produce 1000kg of marketable fruit, the fertilizer requirement is equivalent to nitrogen 3.9-5.5kg, phosphorus pentoxide 2.1-2.3kg, and potassium oxide 4-7.3kg.
Various Management Practices for Greenhouse Cultivation of Zucchini
1. Temperature: Regulate temperature and increase light. After zucchini is planted, the daytime greenhouse temperature should be maintained at 25°C-30°C and nighttime at 18°C-20°C to promote seedling recovery. After seedling recovery, the temperature should be appropriately lowered, controlled at 20°C-26°C during the day and 12°C-15°C at night to promote robust plant growth. After fruiting begins, raise the temperature appropriately, maintaining 25°C-30°C during the day and 15°C-20°C at night. Increase the day-night temperature difference to facilitate nutrient accumulation and fruit expansion. While maintaining the greenhouse temperature, pull up the straw curtains early and lower them late. On cloudy and rainy days, turn on fluorescent lights, hang reflective screens, and spray photosynthetic micro-fertilizer.
2. Fertilization: Strengthen fertilizer and water management. When the first fruit reaches 10 cm in length, apply the first watering, with 25 kg of compound fertilizer applied per mu along with the water. After that, water every 15-20 days for the first watering, and apply topdressing together with watering. Watering is generally done on sunny mornings, not on cloudy days, to prevent lowering the greenhouse temperature and worsening diseases. In addition, because greenhouse temperatures are low and ventilation is limited in deep winter, carbon dioxide fertilization can be attempted.
3. Artificial Pollination: Zucchini is a crop with separate male and female flowers, and under greenhouse cultivation conditions, artificial pollination is required. Method: Between 9-10 AM each day, pick male flowers that opened on the same day, remove the corolla, and gently dab the stamens of the male flower onto the stigma of the female flower to transfer pollen. Each male flower can pollinate 5 female flowers. At the same time, apply a 20ppm 2,4-D solution to the stigma or flower stalk of female flowers to increase the fruit-setting rate. In addition, when there are too many flowers on the plant, appropriately thin the flowers to ensure normal fruit setting.
Vine Hanging and Pruning: For trailing zucchini, after planting and seedling recovery, stretch thin iron wires along the north-south direction at the top of the greenhouse above each row of zucchini, then tie a knot at the stem base to secure it. As the vine grows, tie the vine to the hanging string. When the vine length approaches the greenhouse roof, lower the vine promptly as the lower fruits are harvested, and remove old lower leaves to help prevent disease and improve airflow. Remove side shoots promptly to ensure the growth of the main vine.
4. Pest and Disease Control: The main diseases and pests of greenhouse zucchini include viral disease, gray mold, aphids, and whiteflies. For viral diseases, focus on prevention by eliminating virus-transmitting pests. In the early stage of disease, Dimiejing, Bingduling, and Bingdu No.1 can be used for control; for gray mold, Kemiling and Fangmeiling can be used; for powdery mildew, sulfur suspension concentrate can be used; for aphids, Mieya No.1 can be used; for whiteflies, imidacloprid, buprofezin, or yellow sticky traps can be used for control.