Key Technical Points for Spring and Autumn Open-Field Cultivation and Management of Bottle Gourd (Hu Zi)

Bottle gourd (pinyin: hù zǐ), also known as gan hu, tian hu, hu gua, jing jie chui, long mi gua, tian gua, chang hu, bian pu; it belongs to the phylum Angiospermae, family Cucurbitaceae, genus Lagenaria, and is a variety of the genus plant bottle gourd (Lagenaria siceraria), an annual climbing herb. It differs from the bottle gourd (the original variety) in that: the ovary is cylindrical; the fruit is uniform in thickness and cylindrical, straight or slightly curved, up to 60-80 cm long, greenish-white, with white flesh. When young, the fruit is soft and juicy and can be used as a vegetable. It is cultivated in most parts of the country and widely cultivated in the Yangtze River basin, harvested in summer and autumn.

Plant Morphology of Bottle Gourd

Bottle gourd is an annual climbing herb with soft hairs; tendrils are branched. Leaves alternate, blade heart-shaped ovate to kidney-shaped ovate, 10-40 cm long, width roughly equal to length, slightly angular-lobed or 3-lobed, apex shortly pointed or bluntly rounded, margin with short teeth, base heart-shaped; petiole 5-30 cm long, with 2 glandular teeth at the apex. Flowers solitary, opening in the evening and withering early; male flowers have long stalks, longer than the petiole; female flower stalks are shorter. Calyx 2-3 cm long, funnel-shaped, 5-lobed, lobes narrowly triangular, covered with soft hairs; petals 5, white, broadly ovate or obovate, 3-4 cm long, 2-3 cm wide, margins wrinkled and curved. Male flowers have 3 stamens, anthers connate, one anther with 1 locule, the other two each with 2 locules; female flowers have an elliptical ovary with downy hairs, a short style, and 3 stigmas, each 2-lobed. Fruit obovate-oblong or long club-shaped, slightly soft when young, green; when mature, the outer skin hardens and turns white or yellow. Seeds numerous, white, obovate-oblong, apex truncate or with 2 angles. Flowering period June. Fruiting period July. It is cultivated in most parts of the country. The seeds of this plant (hu zi seeds) and the mature dried fruit rind (pu zhong ke) are also used medicinally, each detailed in separate entries.

Spring and Autumn Open-Field Cultivation and Management Techniques for Bottle Gourd

Variety Selection.

(1) Hefei Xian Hu Zi: early-maturing, high quality, high yield, disease-resistant. Fruit 50-70 cm long, 8-10 cm thick, single fruit weight 1-1.5 kg;

(2) Shucheng Biyu No. 1: extremely early-maturing, disease-resistant, high yield, high quality. Fruit 50-100 cm long, 5-10 cm thick, single fruit weight 0.4-1.2 kg;

(3) Nanjing Noodle Hu Zi: early-maturing, high yield. Fruit 70-100 cm long, single fruit weight 1.5-2 kg;

(4) Wuhan Long Hu Gua: early-maturing, high yield, high quality. Fruit oblong, narrow at the waist and large at the ends. Fruit 65 cm long, transverse diameter 7-8 cm, single fruit weight 1 kg.

Seedling Raising.

(1) Timely sowing and seedling raising: for multi-layer covered cultivation in a large greenhouse, the sowing period is early to mid-January; for arched shed cultivation, sow in early to mid-February; for open-field cultivation, sow in early to mid-March; for autumn-delayed open-field cultivation, sow in early to mid-July; for autumn-delayed large greenhouse cultivation, sow in early to mid-August.

(2) Nutrient soil preparation: mix 7 parts of sterile fertile vegetable garden soil that has never been planted with cucurbits + 2 parts of decomposed dry fine manure soil + 1 part of plant ash; add 1 kg of superphosphate or 0.5 kg of compound fertilizer per cubic meter of nutrient soil, and stir thoroughly.

(3) Seed soaking and sprouting: seed quantity 3-3.5 kg.

① Hot water seed scalding. Put the seeds into 55°C hot water and stir continuously for 15-20 minutes, then when the temperature drops to about 30°C, soak the seeds for 5 hours.

② Chemical seed soaking: after soaking the seeds for 3-4 hours, soak them in 100 times diluted formalin (40% formaldehyde) for 10-15 minutes, or soak in 0.1% potassium permanganate or 10% trisodium phosphate for 20 minutes, or soak in 1% copper sulfate for 5 minutes, then remove, rinse repeatedly with clean water, and then sprout.

③ Sprouting: wrap well with wet gauze, wrap with 1 layer of plastic film on the outside, and sprout at 25-30°C. Rinse with warm water 1-2 times a day; when 80% of the seeds show white sprouts, they can be sown.

(4) Sowing: put nutrient soil into nutrient pots 10 cm in diameter, move them into an arched shed or large greenhouse, and water thoroughly to settle the roots. Insert the sprouted seeds with the sprout opening facing down into the pots, 1 seed per pot, and cover with soil 1-1.5 cm after sowing. Cover the seedbed with film, uncover it during the day and cover it at night, maintaining the bed temperature at 25-30°C. For summer seedling raising, use shade nets to lower the temperature. After emergence, control the bed temperature at 20-25°C, not lower than 15°C at night. Maintain and control a certain temperature and humidity inside the shed. Transplant when there are 4 leaves and 1 heart.

Open-Field Fertilization.

(1) Broadcast base fertilizer: apply 75,000 kg/hm2 of decomposed organic fertilizer and 3,000 kg/hm2 of rice husks or chopped straw, then deep plow.

(2) Soil preparation and bed making: according to different cultivation methods, bed widths vary.

① Open-field plastic film mulching with trellis cultivation. Make beds 1.3 m wide, with ditches 0.4 m wide and 0.2 m deep. Plant 2 rows on the bed, with plant spacing 0.5-0.6 m, planting density about 24,000 plants/hm2. Or make beds 2.7 m wide, planting 1 row on each side of the bed, with plant spacing 0.3 m.

② Large greenhouse, arched shed, and plastic film mulching cultivation. Make beds 1 m wide, with ditches 0.4 m wide and 0.2 m deep. Plant 2 rows per bed, with plant spacing 0.4 m, about 30,000 plants/hm2.

③ Open-field plastic film mulching without trellis cultivation. Make beds 2.7 m wide, with ditches 0.3 m wide and 0.2 m deep. Plant 1 row on each side of the bed, with plant spacing 0.3 m, about 22,500 plants/hm2.

(3) Digging row trenches: dig trenches longitudinally in the planting zone on the bed surface, with trench width 0.3 m and depth 0.4 m.

(4) Applying trench base fertilizer: apply 15,000 kg/hm2 of high-quality decomposed manure; or 1,500 kg/hm2 of dry manure or cake fertilizer; or 600 kg/hm2 of ternary compound fertilizer and 300 kg/hm2 of superphosphate. Stir the fertilizer and soil, level the trench and make ridges.

Transplanting.

Transplant at the appropriate time and age according to different cultivation methods and cultivation seasons. The optimal seedling age is 4 leaves and 1 heart. For multi-layer covered early-maturing cultivation, transplant from late February to early March. It is necessary to water thoroughly to settle the roots, lay plastic film, and cover with arched shed film, straw curtains, and large greenhouse film. For autumn-delayed cultivation, leave in the open field first and then cover with shed film. Plastic film mulching is required for cultivation in all seasons.

Management.

(1) Intertillage and soil loosening: for those without plastic film mulching, loosen the soil 3-4 times before the vines are trained onto the trellis. Hoe shallowly near the roots of the plants and deeply farther from the roots.

(2) Setting up trellises: use 3 m long bamboo poles to build a herringbone trellis, crossing at 1.3 m, and use small bamboo poles to set 2-3 horizontal bars. For bottle gourd cultivated in facility greenhouses, the trellis height inside the shed should preferably not pierce the greenhouse film.

(3) Pinching and vine training: early-maturing trellised bottle gourd may not need pinching. Ground-creeping bottle gourd should be pinched 2-3 times and requires vine pressing. Late-maturing bottle gourd is suitable for flat trellis cultivation; after the vines reach the trellis, leave 6-8 leaves on the main vine, then pinch the main vine and lateral vines immediately.

(4) Artificial supplementary pollination: carry out artificial pollination in the evening.

(5) Temperature and humidity management: for early-maturing cultivation in large greenhouses, after transplanting the key point is to maintain the temperature inside the shed; uncover straw curtains during the day to maintain the daytime temperature inside the shed at 25-30°C, and 18-20°C at night. After seedling recovery, maintain the daytime temperature inside the shed at 25°C and the night temperature at 15°C. On sunny mornings, when the temperature inside the shed rises to 28°C, uncover the film for ventilation; in the afternoon, when the temperature inside the shed drops to 28°C, close the shed. If the humidity inside the shed is too high, increase the extent of film uncovering. When the nighttime temperature outside the shed normally reaches 20°C, the shed film can be removed.

(6) Water and fertilizer management: water thoroughly to settle the roots at transplanting, and water once more after seedling recovery. Before the flowering and fruiting period, apply decomposed manure, organic fertilizer, or compound fertilizer as a top dressing about every 5 days; during the fruiting period, apply manure or compound fertilizer as a top dressing every 10-15 days, while paying attention to controlling water and fertilizer concentration to prevent fruit abortion; after the fruiting period, water promptly, preferably in the morning or evening. Spray the leaves with 0.5% urea plus 0.3% potassium dihydrogen phosphate solution once every 10 days. After each fruit harvest, apply top dressing once. Pay attention to drainage during the rainy season. For greenhouse cultivation, pay attention to ventilation and air exchange, heat preservation, and humidity reduction.

Pest and Disease Control.

(1) Physical control: sterilize and disinfect by exposing seeds to high solar heat, scalding seeds with warm water, and dry heat treatment; freeze the soil in winter to kill insect eggs, use plastic film mulching to kill insects and sterilize, and close the shed at high temperature to kill insects and sterilize.

(2) Chemical control:

① Seedling damping-off and Rhizoctonia rot. Spray 2-3 times at 7-day intervals with 75% chlorothalonil 600 times solution or metalaxyl wettable powder 800 times solution.

② Fusarium wilt. Drench the roots 3 times with 70% dexon 1000 times solution, once every 10 days.

③ Viral disease. Remove diseased plants promptly and control aphids. Fenvalerate and dimethoate can be used for control.

④ Powdery mildew. Spray alternately at 7-day intervals with 75% chlorothalonil 500 times solution, or 25% triadimefon 1500-2000 times solution, or 4% sulfur-polycarbamate suspension concentrate 1000 times solution.

⑤ Cottony leak. Spray for control with 58% metalaxyl-mancozeb 500 times solution, or 64% oxadixyl-mancozeb 500 times solution, or 18% metalaxyl-amine manganese-zinc 800 times solution.

Harvesting.

Harvest at the appropriate time; 15-20 days after flowering, harvest the first fruit promptly. During the peak fruiting period, the harvest period is 11-14 days after flowering. Harvest with disinfected scissors, while preventing contamination by sewage, remove diseased and inferior fruits, and stack neatly.

Seed Saving.

Select the first and second fruits of plants that have the typical characteristics of the variety, are robust, strongly disease-resistant, and bear fruit early for seed saving, and remove all other young fruits and female flowers of that plant. After fruit set, increase the application of phosphorus and potassium fertilizers. The seed fruit needs post-ripening, and the seeds are taken out when sowing the following year.

Difficulties in Autumn-Delayed Bottle Gourd Production and Countermeasures.

At present, the market demand for autumn bottle gourd is relatively large, but because summer and autumn temperatures are high, droughts and floods are severe, and soil-borne diseases in vegetable gardens (such as viral disease, Fusarium wilt, Phytophthora blight, etc.) are relatively serious, bottle gourd cannot grow and develop normally. The countermeasures are as follows:

(1) Select excellent disease-resistant varieties suitable for local growth.

(2) Sow at the appropriate time: the sowing period should avoid the peak growth period falling in the high-temperature season, and arrange the early fruiting stage under 20-25°C temperature conditions. Sowing too early makes plants susceptible to viral disease; sowing too late makes them vulnerable to cold waves.

(3) Strictly treat seeds: combine hot water scalding and chemical seed soaking. The process is as follows: sun the seeds → scald the seeds (55°C water with continuous stirring) → soak the seeds (3-4 hours) chemical seed soaking (10% trisodium phosphate or 40% formaldehyde 100 times solution for 10 minutes) → rinse with clean water → sow.

(4) Seedbed soil disinfection. Use 58% metalaxyl-mancozeb wettable powder 600 times solution plus 40.7% chlorpyrifos 800-1000 times solution, spray the seedbed before sowing to disinfect and sterilize and kill underground pests.

(5) Seedbed cooling. Use shade nets or shade frames to cool the seedbed, and promote female flower formation through short-day treatment.

(6) After emergence, control seedbed moisture to prevent excessive growth. Spray 0.3% potassium dihydrogen phosphate 1-2 times.

(7) At transplanting, first soak the seedlings with roots and soil in 500 times carbendazim solution for 3-5 minutes. If high temperature occurs after transplanting, take shade or shade frame covering to lower the temperature and prevent heavy rain from washing away the seedlings. When the outside temperature is lower than 20°C at the end of September, the large greenhouse film needs to be tightly covered.

(8) Management: after vine growth, remove lateral branches below 10 leaves and guide the vines onto the trellis. Pinch the main vine when it is 0.2 m from the shed top or reaches the top trellis; pinch lateral vines at 2 leaves after the female flower. Carry out artificial pollination every day at 10 a.m. or in the evening. Remove old leaves, yellow leaves, diseased leaves, and ineffective branches at the base promptly to enhance ventilation and light penetration.