Key Points of High-Efficiency Cultivation Techniques for Zucchini in Solar Greenhouses

Zucchini is grown in Shandong, Shanxi, Henan, Hebei and other places, and is a type of pumpkin. Also known as eggplant melon, bear (male) melon, white melon, small melon, foreign melon, horn melon, xun melon, etc. Native to India, it is grown in both southern and northern China. Zucchini has the effects of clearing heat and promoting diuresis, relieving restlessness and quenching thirst, moistening the lungs and stopping cough, and reducing swelling and dispersing nodules.

Morphological Characteristics of Zucchini

Zucchini is an annual trailing herbaceous plant, with three major lines: dwarf, semi-trailing, and trailing. Most varieties have obvious main vine dominance, with few and weak side vines. The stem is stout, cylindrical, with white short bristles. The stem has angular grooves, with short bristles and semi-transparent rough hairs.

Leaves: The petiole is stout, covered with short bristles, 6-9 cm long. The leaf blade is hard in texture, upright, triangular or ovate-triangular, with a sharply pointed tip, irregular sharp teeth along the margin, a heart-shaped base, and a semicircular sinus, 0.5-1 cm deep and 3-4 cm wide; the upper surface is dark green, the lower surface is lighter in color, the veins are slightly raised on the back, and both sides have rough hairs. The tendrils are slightly stout, with soft hairs, and are much branched.

Flowers: Monoecious. Male flowers are solitary; the pedicel is stout, angular, 3-6 cm long, covered with yellowish-brown short bristles; the calyx tube has obvious 5 angles, and the calyx lobes are linear-lanceolate; the corolla is yellow, often gradually narrowed toward the base and bell-shaped, 5 cm long, 3 cm in diameter, split to near the middle, the lobes upright or slightly spreading, with a sharply pointed tip; stamens 3, filaments 15 mm long, anthers connivent, 10 mm long.

High-Efficiency Cultivation Techniques for Zucchini in Solar Greenhouses

1. Variety Selection

Generally, early-maturing and high-yielding varieties are selected, commonly Zaoqing No. 1 zucchini.

2. Crop Rotation Arrangement

For the early spring crop, planting can be 20-30 days earlier than cucumber. For sowing and raising seedlings from December to January, planting in late January to early February is appropriate, with marketing in mid-to-late March and vine removal in early June; for the autumn-winter crop, sow in late August, plant in late September, harvest in early November, and it can be delayed until late April of the following year.

3. Seedling Raising Techniques

1) Strong Seedling Indicators

Plant height 15-16 cm, stem diameter 0.4-0.5 cm, with 2-3 true leaves, short internodes, compact plant shape, well-developed root system, and no pest or disease damage. To achieve the strong seedling indicators, the following should be done when raising seedlings: the soil block should be large (10-12 cm), the seedling age should be short (calendar seedling age 30-35 days), and the temperature should be low (during the seedling period, 18-22°C during the day and 8-10°C at night).

2) Sowing

Each 667 sq m requires 500 grams of seeds. Soak the seeds in 60-62°C warm water for 10-15 minutes for disinfection, then soak the seeds for 8-10 hours, drain them, wrap them in wet gauze, and germinate them at 25-28°C for 48 hours. The mixing ratio of the nutrient soil for seedling raising is half organic matter and half fertile garden soil. Mix thoroughly and put into plastic cups. After watering, sow 1 germinated seed per cup, cover with soil 2.0 cm thick. To increase the ground temperature, heating wires can be laid in the seedling bed.

3) Seedling Stage Management

From sowing to emergence, the daytime temperature is 25-30°C and the nighttime temperature is 16-20°C, and full emergence can occur after 3-4 days; after emergence, in order to prevent the seedlings from becoming leggy, the temperature should be lowered, with daytime temperature 20-22°C and nighttime temperature 10-12°C, which can both make the seedlings grow robustly and promote female flower differentiation. In the later stage of seedling raising, carry out low-temperature hardening of the seedlings, with daytime temperature 18-20°C and nighttime temperature 6-8°C. For seedling raising in plastic cups, the principle of controlling temperature but not water should be mastered; when the seedlings show drought, they should be watered, generally watering 2-3 times during the seedling period. In order to make the seedlings grow uniformly, the method of moving and reversing seedlings should be adopted, placing large seedlings on the south side of the greenhouse seedling bed, and placing smaller seedlings in the middle of the seedling bed where light and temperature are better; when reversing seedlings, the distance between seedling pots can be appropriately increased, so that the seedlings are uniform and robust.

4. Cultivation Techniques

1) Land Preparation and Fertilization

Zucchini has a well-developed root system and strong water and fertilizer absorption capacity. Apply 3-4 tons of fully decomposed organic fertilizer and 20 kg of diammonium phosphate per 667 sq m, plow the land twice to a depth of 20-25 cm. In the fertilization method, a combination of concentrated application and broadcast application can be adopted: spread two-thirds of the organic fertilizer as a broadcast application, and apply one-third of the organic fertilizer in furrows or holes. Then make high ridges with a ridge width of 60 cm, a furrow width of 40 cm, and a height of 15 cm, and then cover with plastic film.

2) Management After Planting

In early spring, when the 10 cm ground temperature is stable above 8-10°C, the air temperature is stable above 3°C, and the daytime temperature above 20°C is maintained for about 5-6 hours, planting can be done around early February, with a row spacing of 1 m, a plant spacing of about 40 cm, and 2000 plants per 667 sq m. Choose a sunny morning at the “end of cold and beginning of warmth”. When planting, dig holes and water the holes, seal the holes with wet soil, and water once more after 2-3 days; after the seedlings survive, choose a sunny day and carry out one furrow irrigation; after watering, when the soil surface appears dry, carry out one intertillage of the ridge furrows to loosen the soil. For the autumn-winter crop, plant in early September, choose a cloudy afternoon; after planting, in order to prevent high-temperature dead seedlings, shade netting can be covered to prevent high temperature and avoid strong light, promoting seedling recovery.

During the flowering and fruit-setting period, the daytime temperature is 20-25°C and the nighttime temperature is above 15°C; during the fruit enlargement period, the daytime temperature is 20-23°C and the nighttime temperature is 13-15°C.

In water and fertilizer management, from the seedling stage to before flowering and fruit setting, the main focus is on intertillage to preserve water and control water and fertilizer, to prevent leggy growth or “crazy vines” due to excessive soil water and fertilizer. When the root melon fruit begins to enlarge, apply 15-20 kg of diammonium phosphate per 667 sq m in combination with irrigation; at the second and third fruit enlargement, carry out the second topdressing, applying 20 kg of urea per 667 sq m. After irrigation and topdressing, pay attention to ventilation and dehumidification to prevent the occurrence of gray mold.

3) Preserving Flowers and Fruits

Zucchini cultivated in greenhouses is prone to fruit abortion, so artificial supplementary pollination must be carried out. The method is: “every day from 6-10 am, pick male flowers, remove the corolla, and gently smear the stamens of the male flowers on the stigma of the female flowers to complete artificial pollination; each male flower can pollinate 3-4 female flowers. Treating the stigma and fruit stalk with 20X10-6 of 2,4-D or 60X10-6 of anti-drop agent can prevent fruit abortion and promote fruit enlargement. Spraying 0.1% Shukening solution on the stigma of young fruits can prevent gray mold from damaging young fruits.

4) Plant Adjustment

1) Vine Hanging

When cultivating zucchini in winter and spring, for good ventilation and light transmission, hang vines with nylon rope for each plant so that the plants grow upright.

2) Pruning and Leaf Removal

Zucchini mainly sets fruit on the main vine, so side branches should be removed as early as possible; zucchini leaves are large and petioles are long, which easily shade light correspondingly, so diseased leaves, yellow leaves, damaged leaves and old leaves should be removed as early as possible, which can promote ventilation and light transmission and prevent the spread of diseases.

3) Renewal Pruning

In the later stage of growth, the middle and lower leaves age and the plant growth vigor is weaker, so the middle and lower leaves should be removed, and 1-2 side branches from the upper part should be selected and, after topping, replace the main vine for fruit setting.

5. Harvesting

1) Harvest in a timely manner in the early stage; when the root melon grows to about 250 g, harvest it early, and deformed melons and large melons should be picked early.

2) Harvest appropriately later in the later stage to increase the weight of individual melons.

6. Pest and Disease Control

1) Aphids: 20% fenvalerate 2000-3000 times solution, 2.5% deltamethrin emulsifiable concentrate 2000-3000 times solution, sprayed evenly.

2) Red spider mites: 10% Uranus emulsifiable concentrate 3000 times solution, 25% propargite wettable powder 1000 times solution.

3) Viral disease: In the early stage of the disease, spray 20% Virus A wettable powder 500 times solution or 1.5% Zhibingling emulsion 1000 times solution, once every 7-10 days, continuously spraying 2-3 times.

4) Powdery mildew: Use 25% triadimefon wettable powder 2500 times solution, once every 5-7 days, continuously spraying 2-3 times.