A Detailed Guide to Planting Time and Fertilization Key Points for Early Spring Greenhouse Zucchini

Zucchini, also called xi hu, xiong (male) melon, white melon, fan melon, American pumpkin, and xiao gua, is now cultivated in many places and is quite rich in nutritional value as a vegetable. Due to market demand, early spring greenhouse zucchini has been developed. So when should early spring greenhouse zucchini be planted? What are the key points for fertilization?

1. When should early spring greenhouse zucchini be planted?

For early spring greenhouse cultivation of zucchini, the suitable sowing period depends on the air temperature at transplanting time, the tolerance of the zucchini variety to low temperatures, and the heat preservation performance of the greenhouse. Zucchini transplanting must be carried out when the soil temperature inside the greenhouse is stably above 11°C and the nighttime air temperature is above 0°C. After determining the safe transplanting period, count back 30-35 days from the transplanting period to get the suitable local sowing period for zucchini. In the Yangtze River Basin, when using cold-frame seedling cultivation, the sowing period for zucchini is generally from late January to early February. When using plastic greenhouses with small arch tunnels as seedling facilities, it can be advanced to December to early Yuan month, using electric heating hotbeds or fermented heating hotbeds for seedling cultivation.

2. What are the key points for fertilizing early spring greenhouse zucchini?

1. Base fertilizer

Choose a loose, fertile plot that has not previously grown crops of the same family as the preceding crop to build the greenhouse, and apply sufficient base fertilizer. Generally, apply 3000-3500 kg of decomposed organic fertilizer per mu. After deep plowing and land preparation, apply 150-200 kg of biological organic fertilizer or 100 kg of cake fertilizer in furrows. Cover the greenhouse about 15 days before transplanting, and keep it sealed after covering to raise the soil temperature. 3-5 days before transplanting, prepare the land and make beds. For double-row planting, the bed width is 1.5 m (including ditches); for single-row planting, the bed width is 1.0 m (including ditches).

2. Topdressing

For zucchini transplanted with plastic film mulching, it is generally not necessary to water for seedling recovery. If no plastic film is laid, water once within 2-3 days after transplanting to help the seedlings recover; the amount of water should be enough to soak through the nutrient soil, and should not be excessive. Afterward, water according to plant growth conditions and soil dryness and moisture. For cultivation with plastic film mulching, furrow irrigation can be used, but drip irrigation is best, and it should be combined with topdressing.

Generally, the first topdressing is applied during the fruit-setting and swelling stage of the first batch of melons, with 15-20 kg of compound fertilizer per mu. The second topdressing is after the first batch of melons is harvested and during the fruit-setting period of the second to third batches of melons, with 8-10 kg of compound fertilizer or 6-7 kg of urea per mu. Afterward, topdressing can be applied according to plant growth conditions.

3. Precautions for planting early spring greenhouse zucchini

1. Sprouting and sowing

If sprouting is needed, wrap the treated seeds in a wet towel and place them in a 25-30°C environment to sprout. During sprouting, rinse the seeds once a day in warm water, drain the water, and continue sprouting. Generally after 2-3 days, when the sprouts are 0.2-0.4 cm long, they can be sown. Before sowing, first check the moisture of the nutrient pots. If they are rather dry, water appropriately. Place the sprouted seeds flat in the nutrient pots with small holes already made in advance, 1 seed per pot. Never insert them upright. After sowing, cover with 1-2 cm of fine soil, cover with plastic film, set up small arch tunnels, close the greenhouse, and keep warm and moist.

2. Temperature management

After transplanting, immediately seal the greenhouse to keep warm, maintaining 28-30°C during the day and 15-20°C at night, preventing low temperatures below 0°C. In case of low temperatures, add straw curtains or use multi-layer film covering. If small arch tunnels are set up inside the greenhouse, uncover the small arch tunnel film during the day and cover it tightly again at night. After seedling recovery, lower the temperature appropriately, maintaining 22-25°C during the day and 12-18°C at night. 4-7 days after transplanting, maintain 25-28°C during the day and about 15°C at night. When the temperature rises above 30°C, ventilate for air exchange. On sunny days at noon, uncover the side skirts for ventilation, and the ventilation openings should be gradually enlarged from small to large. After late April, the small arch tunnels inside the greenhouse can be removed, and even the greenhouse side skirts can be removed.