Cucumber Sowing Methods and Key Points for Seedling Stage Management, with Greenhouse Cultivation Techniques

Cucumber, also known as green cucumber. It is widely cultivated throughout China, and many regions have greenhouse or plastic tunnel cultivation; it is now widely grown in temperate and tropical regions. Cucumber is one of the main summer vegetables in all parts of China. The stems and vines are used medicinally to reduce inflammation, resolve phlegm, and relieve spasms. So how much do you know about the growth habits of cucumber? Regarding cucumber sowing methods, cucumber seedling stage management, and cucumber transplanting techniques, let me introduce them to you one by one.

I. Growth Habits of Cucumber

1. Temperature: Cucumber prefers warmth and cannot tolerate cold. The suitable temperature for growth is 10-32°C. Generally, 25-32°C during the day and 15-18°C at night are best for growth. The most suitable soil temperature is 20-25°C, with a minimum of around 15°C. The most suitable day-night temperature difference is 10-15°C. At high temperatures of 35°C, cucumber photosynthesis is poor; at 45°C, high-temperature damage occurs; at low temperatures of -2 to 0°C, the plants freeze to death. If subjected to low-temperature hardening, they can withstand temperatures as low as 3°C.

2. Light: South China type varieties are relatively sensitive to short-day conditions, while North China type varieties are not strict about day length and have become day-neutral plants. Their light saturation point is 55,000 lux, and their light compensation point is 1,500 lux. Most varieties grow well under short-day conditions of 8-11 hours.

3. Water: Cucumber has high yields and high water requirements. The suitable soil moisture is 60-90%. During the seedling stage, water should not be excessive, with soil moisture at 60-70%. During the fruiting stage, sufficient water must be supplied, with soil moisture at 80-90%. The suitable relative air humidity for cucumber is 60-90%. If the relative air humidity is too high, diseases are very likely to occur, causing reduced yields.

4. Soil: Cucumber likes moisture but cannot tolerate waterlogging, and likes fertilizer but cannot tolerate excessive fertilizer. It is best to choose fertile soil rich in organic matter. It generally prefers soil with a pH between 5.5 and 7.2, but a pH of 6.5 is best.

II. Cucumber Sowing Methods

1. Variety selection: For cucumber cultivation, choose excellent varieties that tolerate low temperatures in the early stage, tolerate high temperatures in the later stage, and have strong disease resistance, such as Jinyou No. 10, Bonai No. 3, etc.

2. Seed treatment: 1-3 days before sowing cucumber, sun-dry the seeds. After sun-drying, scald the seeds in 55°C warm water for 10-15 minutes, stirring constantly until the water temperature drops to 30-35°C. Rub and wash the seeds repeatedly, rinse off the mucus with clean water, and soak for 3-4 hours. Wrap the soaked seeds in a clean wet cloth and place them under conditions of 28-32°C to germinate for 1-2 days. Sow when 70% of the seeds have “sprouted white”.

3. Soil preparation: For cucumber nutrient soil, mix garden soil or field soil that has not grown cucurbit vegetables in the past 3-5 years with high-quality decomposed organic fertilizer. Organic fertilizer accounts for 30%. Mix the soil and organic fertilizer evenly and sift. For every 1 cubic meter of soil, add 100 grams of carbendazim to the sifted nutrient soil and mix evenly to make medicated soil.

4. Timely sowing: The sowing period for cucumber is mid-January or late January. Seedlings can be raised in heated greenhouses or energy-saving solar greenhouses. Use nutrient pots with a diameter of 10 cm and a height of 10 cm, filled with 8 cm of nutrient soil. Water thoroughly. After the water drains through, sow 1 germinated seed in each nutrient pot, cover with 1 cm of medicated soil, and lay plastic film flat on top to help preserve moisture.

III. Cucumber Seedling Stage Management

1. Plastic film mulching: After sowing cucumber, seal with plastic film for 2-3 days. When cotyledons of 2/3 of the seeds emerge from the soil, remove the plastic film promptly. During the seedling stage, water as little as possible to prevent leggy seedlings caused by high temperature and high humidity, and remove straw mats promptly to increase light exposure.

2. Temperature management: Generally, the daytime temperature should be controlled at 25-30°C and should not be too high. The nighttime temperature must be controlled below 15°C, preferably 12-13°C. 7-10 days before transplanting, carry out hardening. Remove greenhouse straw mats early and cover them late, reduce watering, and increase ventilation amount and time. Maintain 20-25°C during the day and 8-10°C at night, and provide 1-2 short periods of 5°C hardening.

3. Standards for strong seedlings: Seedling age about 35 days, plant height 15-20 cm, 3 leaves and 1 heart, cotyledons intact, short and thick internodes, dark green and thick leaves, well-developed root system, robust and disease-free.

IV. Cucumber Transplanting Techniques

1. Land preparation and fertilization: Fertilization should be mainly organic fertilizer, supplemented by chemical fertilizer. The fertilization method should be mainly base fertilizer, supplemented by topdressing. According to the nutritional characteristics of vegetable growth and development, fertilizer requirement patterns, soil nutrient content, and target yield, use an expert fertilization system to determine the fertilizer application rate for vegetables, carry out balanced fertilization, and ensure nutrient balance in the soil. For vegetable plots with medium fertility, generally apply 5,000 kg of high-quality decomposed organic fertilizer, 20 kg of urea, 75 kg of superphosphate, and 30 kg of potassium sulfate per mu. After broadcasting the base fertilizer, plow deeply 30-40 cm, mix the soil and fertilizer evenly, rake level, and make beds 1.2 m wide. Within each bed, form two high ridges 10-15 cm high with a ridge spacing of 50 cm.

2. Four-film mulching: In early spring greenhouses, use “four-film mulching”, namely one layer of greenhouse film, two layers of overhead screen film, and one layer of small arch film over the seedlings. Cover the greenhouse film 20 days before transplanting to increase soil temperature. Transplant when the 10 cm soil temperature inside the greenhouse has stably passed 12°C for 3 consecutive days. Hang 2 layers of overhead screens 5-7 days before transplanting, with a spacing of 20-30 cm. It is best to choose polyethylene non-drip plastic film with a thickness of 0.012 mm.

3. Timely transplanting: Spray a fungicide once on the seedbed 1 day before transplanting. You can choose 50% carbendazim 500 times solution, or 77% Kocide 700 times solution, or 75% chlorothalonil 1000 times solution. Transplanting should be carried out on a sunny morning. Open ditches on the ridges and water. When the water seeps to half the ditch, place seedlings at a plant spacing of about 32 cm. After the water seeps in, seal the ditch with soil. This method is called “water-stabilized seedlings”. Transplant about 3,500 plants per mu. After transplanting, cover the beds with small arch films.