A detailed guide to greenhouse cucumber cultivation techniques and key management points
Cucumber, also known as hujia, cigua, wanggua, qinggua and so on, is an annual trailing or climbing herbaceous plant of the genus Cucumis in the Cucurbitaceae family. It was first brought back to the Central Plains by Zhang Qian on his mission to the Western Regions during the Western Han Dynasty. It is now widely grown in temperate and tropical regions, and is commonly cultivated throughout China, with greenhouse or plastic tunnel cultivation in many areas. Let us take a look at greenhouse cucumber cultivation techniques below!
Cucumber growth habits
1. Temperature: Cucumber likes 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 give the best growth; the most suitable soil temperature is 20-25°C, with a minimum of about 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 -2-0°C, the plants freeze to death. If cold-hardened at the seedling stage, 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 have no strict requirements for 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 a large water requirement. The suitable soil moisture is 60-90%. During the seedling stage, water should not be too abundant, 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, disease occurs easily, 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.
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 and Bonai No. 3.
2. Seed treatment: Sun the seeds for 1-3 days before sowing. After sunning, scald the seeds in warm water at 55°C for 10-15 minutes, stirring constantly until the water temperature drops to 30-35°C. Rub and wash the seeds repeatedly, wash off the mucus with clean water, and soak for 3-4 hours. Wrap the soaked seeds in a clean damp cloth and place them at 28-32°C to germinate for 1-2 days. Sow when 70% of the seeds have “whitened” (sprouted).
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, with organic fertilizer accounting for 30%. Mix the soil and organic fertilizer evenly and sieve. To the sieved nutrient soil, add 100 g of carbendazim per 1 cubic meter of 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 10 cm in diameter and 10 cm high, filled with 8 cm of nutrient soil. Water thoroughly; after the water drains, 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.
Cucumber seedling-stage management
1. Plastic film covering: After sowing cucumber, seal with plastic film for 2-3 days. When 2/3 of the seeds have their cotyledons emerge from the soil, remove the plastic film promptly. Water as little as possible during the seedling stage 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 night temperature must be controlled below 15°C, preferably 12-13°C. 7-10 days before transplanting, harden the seedlings: uncover straw mats early and cover them late, reduce watering, and increase ventilation amount and duration. Keep 20-25°C during the day and 8-10°C at night, and carry out 1-2 short periods of hardening at 5°C.
3. Standards for strong seedlings: Seedling age about 35 days, plant height 15-20 cm, 3 leaves and 1 heart, intact cotyledons, short and thick internodes, dark green and thick leaves, well-developed root system, robust and disease-free.
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 land 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 spreading the base fertilizer, plow deeply 30-40 cm, mix the soil and fertilizer evenly, rake level, make beds 1.2 m wide, and form two high ridges 10-15 cm high in the bed with a ridge spacing of 50 cm.
2. Four-film covering: In early spring, greenhouses use “four-film covering”, namely one layer of greenhouse film, two layers of overhead curtain film, and one layer of small arch film above the seedlings. Cover the greenhouse film 20 days before transplanting to raise 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 curtains 5-7 days before transplanting, spaced 20-30 cm apart. It is best to use polyethylene anti-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 done on a sunny morning. Open a furrow on the ridge and water; when the water seeps to half the furrow, place the seedlings at a plant spacing of about 32 cm. After the water seeps in, seal the furrow with soil. This method is called “water-stabilized seedlings”. Transplant about 3,500 plants per mu, and after transplanting cover the bed with a small arch film.
Cucumber field management
1. Temperature management: Just after transplanting, the soil temperature is relatively low, so the greenhouse should be closed immediately. Even if the short-term temperature exceeds 35°C, do not ventilate, so as to raise the soil temperature as quickly as possible and promote seedling recovery. During the seedling recovery period, if there is no excessively high temperature, no ventilation is needed. Open the small arch film promptly in the morning to raise the soil temperature as quickly as possible. After seedling recovery, ventilate timely according to weather conditions, ensuring that the time at 21-28°C is more than 8 hours, and maintain the nighttime minimum temperature at about 12°C. As the outside temperature rises, gradually increase the ventilation opening. When the outside temperature stabilizes above 12°C, ventilate day and night. The best greenhouse temperature is 25-30°C in the morning and 20-25°C in the afternoon.
2. Intertillage and loosening soil: After cucumber seedling recovery, carry out 3-4 intertillage and soil loosening operations, from near to far and from shallow to deep. Combine intertillage with hilling the cucumber seedlings, ultimately forming small high-ridge cultivation.
3. Reasonable watering: After transplanting cucumber, water once to help seedling recovery; afterward, do not water unless the soil is dry. When the cucumber has grown to 12 leaves and about 60% of the vines have small cucumbers about 12 cm long, water the second time. After entering the fruiting stage, the water requirement increases. Adjust the watering interval according to factors such as growth vigor and weather. In the early growth period, water once every 7-10 days; in the middle period, water once every 5-7 days; in the later period, water once every 3-5 days. In the early period, watering on a sunny morning is best.
4. Timely topdressing: After cucumber enters the fruiting stage, topdress in combination with watering generally applying fertilizer with every other watering. Each time, apply 3 kg of urea and 5 kg of potassium sulfate per mu, or 10 kg of high-nitrogen-potassium water-soluble fertilizer.
5. Humidity control: The relative humidity in the greenhouse for cucumber should be controlled below 85%, and as far as possible the leaves should not form dew or drip water. It is best to use long-life anti-drip fog-reducing greenhouse film. After watering on a sunny morning, first close the greenhouse to raise the temperature to 33°C, then slowly open the ventilation opening to release moisture. When the temperature drops to 25°C, close the ventilation opening. Do this 2-3 times a day for 2-3 consecutive days to reduce the air humidity in the greenhouse.
6. Plant adjustment: When the plant grows to 7-8 leaves and is about 25 cm tall, remove the small arch film and begin stringing. Side shoots below the first cucumber should be removed as early as possible, and the shoots before the cucumber should be pinched after leaving 2 leaves. When the main vine grows to 25 leaves, pinch the growing point to encourage the production of second-crop cucumbers. The root cucumber should be harvested promptly to avoid dragging down the vine.
7. Removing the arch film: The small arch film is generally removed 15-20 days after transplanting, when stringing begins. As the outside temperature rises, gradually remove the overhead curtains to increase light transmittance. Generally, remove the lower overhead curtain in mid-March, and remove the second overhead curtain at the end of March and the beginning of April.
Cucumber pest and disease control
1. Downy mildew
[Symptoms] Downy mildew is a fungal disease, and its affected parts are the middle and upper leaves of cucumber. When observing in the field, the following points should be grasped: around 8 a.m. each day, check whether there are water-soaked, angular lesions on the underside of the leaves, and whether there is a gray mold layer on the lesions. If these three points are present, it can be diagnosed as downy mildew.
[Chemical control] You can choose Anke, Previcur, Mieke, cymoxanil mancozeb, Yikuaijing, Jindleidomier and Amistar. In addition, when controlling downy mildew, pay attention to the simultaneous occurrence of bacterial angular leaf spot. You can add a bactericide for bacterial angular leaf spot to the chemicals used for controlling downy mildew.
2. Gray mold
[Symptoms] It can damage cucumbers, leaves and stems. When damaging the fruit, it often first infects the fallen flowers, causing the flowers to rot. After growing a light gray-brown mold layer, it further infects the young cucumbers. The affected small cucumbers quickly soften, shrink and rot, and are densely covered with a gray-white mold layer. Leaf disease mostly appears as round, nearly round to irregular lesions, 20-50 mm in diameter, with obvious edges, light reddish-brown on the surface, and a small amount of gray mold. When the stems are affected, local rot occurs. In severe cases, the diseased stems break, and the whole plant dies.
[Chemical control] In protected cultivation, in the early stage of disease, you can choose 10% procymidone smoke agent or 45% chlorothalonil smoke agent, 250 g per mu each time, fumigating for 3-4 hours. You can also use 50% iprodione wettable powder 1500 times solution, or 2.5% triflumizole wettable powder 600 times solution, or 50% limeimeikang 500 times solution, or 25% Amistar suspension concentrate 1500 times solution. Apply once every 6-7 days, continuously for 3-4 times. The spray must reach the flowers and young cucumbers. When treating flowers at the beginning of flowering, adding 0.1% of 50% procymidone wettable powder or 25% triflumizole wettable powder 200-300 times solution to dip or spray the flowers has an obvious effect.
3. Powdery mildew
[Symptoms] First, small round powdery mildew spots appear on the upper or lower surface of the lower leaves, gradually expand, become thick and dense, and soon join into one patch. In the later stage of the disease, the entire leaf is covered with white powder, then turns gray-white, and finally the leaf becomes yellow-brown and dried up. Similar lesions also appear on stems and petioles, densely covered with white powdery mildew spots. In autumn, sometimes yellow-brown small granules appear on the lesions, later turning black. This disease is characterized by the leaves being covered with white powder, and in the early stage of the disease the epidermis under the mold layer remains green, making it easy to distinguish from other leaf diseases.
[Control methods] Powdery mildew fungi are particularly sensitive to “sulfur”. Before transplanting, use 1.8 kg of sulfur powder per mu plus sawdust or other combustion-supporting agents, ignite and fumigate, keep the greenhouse closed and fumigate for a whole day and night, which can kill the powdery mildew fungi. Fumigate again after 3 days, then sow or transplant. During cucumber growth, sulfur powder can be reduced by half and the time reduced to one night, then fumigate again after 5-7 days, with good results. When central diseased plants appear in the field, spray pesticides promptly for control. You can choose 20% triadimefon wettable powder 1000 times solution or 75% Daconil wettable powder 500-600 times solution, or 10% Score 2500 times solution, or 2% Kasumin 400 times solution, etc., spraying once every 5-7 days, and use pesticides alternately. When spraying, do not neglect spraying the ground.
4. Viral disease
[Symptoms] Cucumber viral disease mainly damages leaves and cucumbers. It can occur at the seedling stage and adult plant stage. When seedlings are affected, the cotyledons turn yellow and wither, and the young leaves show a mosaic pattern of dark green and light green. When adult plants are affected, the plants are short, the internodes are short and thick, the leaves are obviously wrinkled and thickened, and new leaves show yellow-green mosaic patterns. In severe cases, the diseased leaves curl backward, and the old leaves at the lower part of the diseased plant gradually turn yellow and dry. After the cucumber fruit is affected, growth stops, and the surface shows light and dark green mottling. In severe cases, the cucumber surface is uneven or deformed. In severely affected plants, the internodes shorten, small leaves cluster, no cucumbers form, and the plants shrink and die.
[Control methods] When raising seedlings, use shade nets to lower temperature and reduce light, and keep away from diseased crops. Immediately after transplanting, spray and drench the roots with “Tianda 2116” 1000 times solution + Tianda Yufeng 1000 times solution to promote seedlings and prevent disease. In the early stage of disease, spray with 20% Dukexing 500 times solution or 20% Virus A 500 times solution, once every 7 days.
5. Bacterial angular leaf spot
[Symptoms] At the seedling stage, round or oval water-soaked lesions appear on the cotyledons, slightly sunken, later turning brown and dry. At the adult plant stage, needle-sized water-soaked spots first appear on the leaves. The lesions expand and are limited by the leaf veins, becoming angular, yellow-brown. When humidity is high, milky white mucus is produced on the lesions on the underside of the leaves, and after drying it forms a white film or white powdery substance. In the later stage, the lesions are brittle and easily perforated. Lesions on stems, petioles and young cucumber fruits are water-soaked, nearly round to oval, later light gray, and the lesions often crack. When moist, bacterial ooze overflows from the diseased parts on the cucumber fruit. The lesions expand into the interior of the cucumber fruit, and the flesh along the vascular bundles changes color, extending all the way to the seeds, causing seed contamination. Diseased cucumbers rot in the later stage and have a foul odor. Affected young cucumbers often rot and drop early.
[Control methods] In the early stage of disease, spray with Xinzhiromycin 5000 times solution, or 30% copper fatty acid (DT fungicide) wettable powder 500 times solution, or 77% Kocide wettable powder 400 times solution, or 47% Kasugamycin-copper wettable powder 600-800 times solution. The above chemicals can be used alternately, spraying once every 7-10 days, continuously 3-4 times. Excessive use of copper preparations can easily cause phytotoxicity, generally no more than 3 times. Spray carefully and thoroughly on both the upper and lower surfaces of the leaves to improve control effects.
6. Root-knot nematode
[Symptoms] Root-knot nematodes mainly damage the roots. After the roots are affected, development is poor, with many lateral roots, and spherical or conical nodules of varying sizes form at the root tips, sometimes in strings. They are initially white and soft, later turning brown to dark brown, and the surface is sometimes cracked. The aboveground parts of affected plants develop poorly, the leaves are yellow, and in dry weather they wilt and die, easily mistaken for Fusarium wilt-infected plants.
[Control methods] Before planting, apply 80 kg of calcium cyanamide per mu in combination with deep plowing. Disinfect the soil with 1.8% abamectin EC at 1-1.5 mL per square meter mixed with 6 L of water, or apply 4-6 kg of 3% Miral granule per mu mixed with 50 kg of dry fine soil and broadcast. During the growing period, drench the roots with 1.8% abamectin EC 1000-1500 times solution 1-2 times, with an interval of 10-15 days. After harvest, thoroughly remove diseased and residual plants from the field, burn them in a centralized manner or bury them deeply, and they can be used for composting. In addition, applying 2 tons of biogas residue per mu can effectively control root-knot nematodes. Where conditions permit, planting one crop of rice after vegetable harvest has an even better effect.
7. Whitefly
[Symptoms] Whitefly has very diverse feeding habits and can damage many kinds of vegetables. It mainly damages as nymphs, gathering on the underside of cucumber leaves to suck sap, causing leaves to fade, turn yellow and wilt, and in severe cases the plants die. When damaging, it also secretes honeydew, contaminating leaves, causing mold infection, affecting plant photosynthesis, and seriously affecting yield and quality.
[Control methods] Try to avoid mixed planting, especially cucumber, tomato and common bean, which must not be mixed. Adjusting the production sequence is also an effective method, that is, arrange celery, sweet pepper and other vegetables less damaged by whitefly in the first crop, and then plant cucumber and tomato in the next crop. Older nymphs are mostly distributed on the lower leaves, so remove old leaves and burn them. Setting yellow boards in the greenhouse can effectively control whitefly. Use a knapsack power fogger to atomize 1% deltamethrin or 2.5% fenvalerate (sumicidin) oil into droplets suspended in the air to kill adults, with very good results. You can use 25% buprofezin (Applaud) wettable powder or 2.5% deltamethrin or 20% fenvalerate (Sumicidin) EC 2000 times solution spray once every 6-7 days, continuously for 3 times. Smoke agents can also be used for fumigation, continuously 2-3 times.
How to manage greenhouse cucumbers in winter? Key winter management points for greenhouse cucumber cultivation
In recent years, with the development of protected agriculture, the planting area of greenhouse cucumbers has also continued to increase. In the process of greenhouse cucumber cultivation, doing a good job in winter management is the key, and it is the key to achieving cucumber planting yield and benefits. So how should greenhouse cucumbers be managed in winter? The key winter management points for greenhouse cucumber cultivation are introduced as follows.
Photo: Greenhouse cucumber
I. Cultivate high-quality cold-tolerant strong seedlings
Cold-tolerant varieties mainly include Aoni, a thornless mini cucumber seed. Its characteristics: This variety is an all-female thornless mini cucumber introduced from the Netherlands, indeterminate growth type, early maturing, compact plant growth with strong vigor, main vine bearing fruit, short internodes, 1-2 cucumbers per node, cucumbers at every node, cucumber length about 16 cm, strong continuous fruit-setting ability, dark green color, glossy, sweet taste, extremely high yield, strong cold tolerance, high fruit-setting rate under high temperature and high humidity. Strong stress resistance, highly resistant to downy mildew, powdery mildew, Fusarium wilt and viral disease and other pests and diseases, no dead plants, suitable for autumn delayed, overwintering, early spring and summer protected cultivation. There is also Shengdong No. 3 cucumber seed. Characteristics of this variety: It is a first-generation hybrid, with vigorous plant growth, medium leaves, mainly main vine bearing fruit, dense fruit set, fast fruit growth, no vine rest, strong continuous fruit-setting ability, straight fruit, light green skin and flesh, sweet taste, cucumber length about 35 cm, low deformed fruit rate, high marketable fruit rate, single fruit weight about 200 g, strong disease resistance. Both parents are disease-resistant parents, highly resistant to Fusarium wilt, downy mildew, angular leaf spot and powdery mildew, tolerant to low temperature and weak light. Overwintering cultivation yield is about 25,000 kg per mu, harvest period can reach more than 200 days, suitable for greenhouse early spring, autumn delayed and overwintering crop cultivation.
Photo: Greenhouse cucumber
II. Fertilizer and water management
In mid-to-late February, most winter warm greenhouses' cucumbers enter the peak fruiting period, and the demand for fertilizer and water gradually increases. Therefore, cucumber topdressing should be carried out after the end of February. Generally, apply 20 kg of urea, 5-8 kg of monopotassium phosphate, or 30-35 kg of potassium sulfate compound fertilizer per mu, once every 20 days. According to the situation, combine with watering and apply decomposed human manure and urine or soybean cake water with the irrigation water. At the same time, every 10-15 days, in combination with disease control, carry out foliar topdressing. You can spray a 0.2% monopotassium phosphate solution or a sugar-nitrogen solution prepared with sugar, urea, monopotassium phosphate, and water in a ratio of 1:1:0.2:100, or 500 times Pengdebao nutrient solution, etc. At the end of February and the beginning of March, apply 1 additional round of carbon dioxide gas fertilizer, which can obviously prevent premature aging of plants, improve stress resistance, and extend the fruiting period. In the middle and later stages, the frequency and amount of watering should also increase, but it must be done according to actual conditions to prevent the soil temperature from dropping too much. Generally, it is advisable to keep the soil temperature after watering not lower than 15°C. Prevent seedlings from becoming leggy. In addition to measures such as uncovering covers in a timely manner, increasing ventilation, extending ventilation time, enhancing light intensity and carrying out low-temperature hardening, chlormequat can be sprayed to suppress it. Chlormequat can also enhance the cold resistance and disease resistance of seedlings. Note that the concentration must not be too high.
Photo: Greenhouse cucumber
III. Temperature regulation
After March, the outside temperature gradually rises. During this period, make full use of uncovering and covering straw curtains and opening and closing ventilation openings to regulate the temperature inside the greenhouse, keeping the greenhouse temperature at 26°C-30°C during the day and at 12°C-14°C before pulling up the curtains in the morning, so as to facilitate normal cucumber growth. Pruning and lowering vines: Through pruning and lowering vines, keep the plant height at about 1.3 m, lower in the south and higher in the north, to facilitate light exposure. The specific method is to lower the vines at the base of the cucumber stems and coil them on the ground, so that the growing point of the cucumber plant is at a height of about 1.3 m, keeping the tops of the cucumbers in the entire greenhouse basically on the same plane, and remove old leaves and diseased leaves, keeping more than 20 effective leaves per plant. Reasonable harvesting: For marketable cucumbers, generally keep 2-3 cucumbers that are expanding per plant. Those with strong growth vigor can keep more and harvest later, while weaker ones can keep fewer and harvest earlier.
IV. Disease control
During this period, cucumber is prone to diseases mainly including downy mildew, angular leaf spot, gray mold, powdery mildew, etc. Pests mainly include aphids, whitefly, leafminers, etc. The above pests and diseases should be prevented mainly and controlled comprehensively. In seedling management, carry out chemical control treatment once a week, using broad-spectrum fungicides such as chlorothalonil, carbendazim, Kocide and so on in rotation. In rainy weather, it is recommended to use smoke agents instead of spray control, which can achieve better results.
[Editor's concluding remarks]Cultivating high-quality cold-tolerant strong seedlings and doing a good job in fertilizer, water and temperature regulation are the key tasks in winter greenhouse cucumber management. The above has introduced the key winter management points for greenhouse cucumber cultivation, hoping to be helpful to everyone!
The complete set of greenhouse cucumber cultivation techniques!
Greenhouse cucumbers sell very well on the market, and many people like them quite a lot. Today we will share with everyone the complete set of greenhouse cucumber cultivation techniques!
The complete set of greenhouse cucumber cultivation techniques:
Cucumber has always been a relatively best-selling vegetable variety on the market, and it is also widely planted. Planting methods mainly include protected cultivation and open-field cultivation. Because greenhouse cultivation has a controllable maturity period, doubled yield, and relatively high economic benefits, it has become the main cultivation mode in various regions.
Cucumber growth habits
Cucumber is a crop that likes warmth, likes weak light, tolerates moisture, and sets fruit parthenocarpically. It likes fertilizer and water, grows quickly, and bears many fruits, but its root system is mainly distributed in the shallow plow layer of 15-25 cm, and the leaf surface has a large transpiration rate. The plant stems are thin, the ability to tolerate fertilizer and water is weak, and the absorption capacity is relatively poor.
Cucumber growth stages
Germination stage: From seed germination to the appearance of the first true leaf, lasting 5-10 days. At this stage, the amount of growth is small and the speed is slow, requiring relatively high temperature and humidity and sufficient light.
Seedling stage: From the appearance of cotyledons to before transplanting, the plant has 4-5 leaves, lasting 30-45 days. At this stage, flower bud differentiation begins, but the growth center is still vegetative organs such as roots, stems and leaves.
Vining stage: From seedling transplanting to the setting of the first cucumber. At the end of this stage, the stem height is about 30-40 cm, with 7-8 true leaves unfolded, lasting 10-20 days. Vegetative growth is dominant, gradually transforming to reproductive growth.
Fruiting stage: From the setting of the root cucumber to the end of vine pulling. The fruiting stage of open-field cucumber is about 40 days, while that of greenhouse cucumber is longer, about 120-150 days. At this stage, plant growth slows down, with fruit and flower bud development as the center.
Cucumber requirements for the cultivation environment
Temperature: Cucumber likes warmth and cannot tolerate cold. The suitable temperature during the growth period is 10-32°C. Generally, 25-32°C during the day and 15-18°C at night give the best growth; the most suitable soil temperature is 20-25°C, with a minimum of about 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 -2-0°C, the plants freeze to death. If cold-hardened at the seedling stage, they can withstand temperatures as low as 3°C.
Light: South China-type varieties are relatively sensitive to short-day conditions, while North China-type varieties have no strict requirements for 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.
Water: Cucumber has high yields and a large water requirement. The suitable soil moisture is 60-90%. During the seedling stage, water should not be too abundant, 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, disease occurs easily, causing reduced yields.
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.
Key points of greenhouse cucumber cultivation techniques
Pre-sowing preparation
Select good varieties: According to local environmental conditions, choose varieties that tolerate low temperatures in the early stage, tolerate high temperatures in the later stage, have strong disease resistance, strong growth vigor, and high yield.
Seedbed preparation: For seedbed nutrient soil, choose 6 parts of garden soil that has not grown cucurbit crops, 3 parts of fully decomposed and sieved organic fertilizer, and 1 part of biological bacterial fertilizer, mix and sieve. The sieved nutrient soil can be mixed with some chemicals to control seedling damping-off, Rhizoctonia rot, etc.
Seed soaking and germination: Sun the seeds for 1-3 days before sowing, then scald the seeds in warm water at 55-60°C for 5-10 minutes, stirring constantly until the water temperature drops to 30-35°C. Rub and wash the seeds repeatedly, wash off the mucus with clean water, and soak for 3-4 hours. You can also soak the seeds with 1000 times carbendazim or thiophanate-methyl for 1 hour, rinse with clean water, then soak in clean water for 4 hours, then remove and rinse once, shake off the water, wrap in a damp cloth, and place at 28-32°C to germinate for 1-2 days. When 70% of the seeds have whitened, they can be sown.
Seedling-stage management: After the cotyledons flatten, transplant promptly. During the seedling stage, turn the seedlings 2-3 times, and give variable temperature management at the seedling stage, that is, different temperature management at different growth stages, day and night, sunny and cloudy days. Spray foliar fertilizer twice during the seedling stage, promote and control water appropriately, enhance light as much as possible, remove weeds promptly, and control pests and diseases. Before transplanting, control water and lower temperature, and strengthen ventilation hardening. When the seedlings grow to 5-6 leaves and the seedling age is 55-60 days, prepare to transplant.
Land preparation
The roots and stems of cucumber seedlings have a relatively high water content, are brittle and easy to break, and are both afraid of flooding and unable to tolerate drought. Therefore, when preparing land, make the ground level and slightly sloped to one side to facilitate drainage and irrigation, and the soil should be free of large clods and rich in organic matter.
Clear residual stubble from the greenhouse and plow and sun the soil in advance. Prepare land before transplanting and apply sufficient base fertilizer. Because greenhouse cucumber has a long fruiting period, long-acting organic fertilizer should be the main fertilizer, with nitrogen, phosphorus, potassium, calcium, magnesium and other medium and trace fertilizers applied in combination.
Cucumber likes nitrate nitrogen. When only ammonium nitrogen is supplied, the leaves become smaller, growth is slow, and the absorption of calcium and magnesium decreases. Calcium deficiency physiological disorders often occur, which reduces yield, so timely supplementation should be noted.
The soil itself has low magnesium content. Excessive application of potassium fertilizer and nitrogen fertilizer also hinders magnesium absorption, especially in greenhouse cucumber cultivation; large harvests without applying sufficient magnesium fertilizer will cause magnesium deficiency in cucumber. Sufficient magnesium-containing fertilizer should be applied before cultivation.
For plots with poor soil fertility, apply Sea Elf biostimulant with the base fertilizer to improve the soil environment and balance nutrients.
After preparing the land, draw lines and open furrows to form ridges along the north-south direction. Use wide and narrow rows and small high beds with plastic film mulching cultivation, and water by hidden irrigation under the film or drip irrigation under the film. The wide row spacing is 80 cm, the narrow row spacing is 40 cm, and the ridge height is 20-25 cm. After forming ridges, seal the openings tightly one week before transplanting to raise soil temperature.
Transplant at the right time
Transplant when the temperature of the 10 cm soil layer is stably above 12°C and the nighttime temperature is not lower than 5°C. Be sure to strictly grasp the transplanting period according to specific cultivation conditions, and do not blindly advance it.
Before transplanting, pay attention to the weather conditions and choose five consecutive sunny days for transplanting. One day before transplanting, spray the ground with azoxystrobin + metalaxyl-M mancozeb, which can effectively prevent the occurrence of downy mildew.
When transplanting, spread Bacillus subtilis in the transplanting holes at 23 kg per mu, which has antibacterial and disease-preventing effects. Note that transplanting should not be too deep, and after transplanting the transplanting water must be watered evenly to ensure every seedling is thoroughly watered.
Management after transplanting
Seedling recovery stage: Within 1 week after transplanting, strengthen insulation, close doors and windows tightly, hang door curtains well, and do not ventilate unless the temperature exceeds 33°C. If a cold wave occurs, strengthen insulation. About 10 to 15 days after transplanting, drench the roots once with azoxystrobin + kasugamycin copper.
When the heart leaves are seen growing, it indicates that the seedlings have recovered. The water requirement increases, so water promptly to help seedling recovery. You can drench with Sea Elf biostimulant 200-300 times solution, which helps crops root quickly and promotes seedlings rapidly.
Early flowering stage: From the seedling recovery stage to the setting of the root cucumber, the main task is to promote roots and control seedlings, laying a foundation for the fruiting stage. After seedling recovery, insert supports and tie vines promptly, bending and tying tall vines so that the tops of both tall and short vines are on the same horizontal line, which is convenient for management. Appropriately control water to squat seedlings, so as to facilitate rooting.
If the plant grows too slowly, the leaves are dark green and lack luster, and the growing tip is tightly clustered, it indicates water deficiency; if the petioles and internodes are too long, the leaf color is light green, the leaves are upturned, and the leaves near the growing point are sparse, it indicates excessive water.
Implement large temperature difference management. When the daytime greenhouse temperature exceeds 35°C, ventilate to cool down. When it is 20-25°C in the afternoon, close the ventilation. The nighttime temperature should be kept at 10-13°C. The ventilation method is to first open doors and windows. As the outside temperature rises, you can roll up the film at the shoulder pressed on the apron and open a gap for ventilation.
From the vining stage to before flowering, apply 3 kg of balanced macroelement fertilizer + 2 kg of Sea Elf biostimulant per mu with irrigation to promote flowering and fruiting.
Fruiting stage: Sufficient water and fertilizer should be supplied to promote fruit setting and prevent premature aging. Increase ventilation to cool down and remove moisture. Open gaps or uncover the film at the bottom edge of the greenhouse for ventilation to avoid nighttime condensation. The ventilation opening area should reach 25% of the total covered area, and nighttime humidity should preferably be controlled below 65%.
Wait until the cucumber fruit has set and grown to 10-15 cm, then water with fertilizer, and gradually begin to enter the normal watering and fertilizer flushing stage, supplementing foliar fertilizer at the right time.
Mainly use fertilizers with high nitrogen and high potassium, and appropriately add Sea Elf biostimulant containing mineral-source humic acid to improve soil physical and chemical properties and raise nutrient levels. When severe fruit abortion is found, with enlarged leaves and many deformed cucumbers, use 0.2 kg of phosphorus-potassium source dissolved in 100 kg of water with stirring and spray on the leaves, once every 3-5 days, which can effectively alleviate it. If other trace elements are lacking, pay attention to supplementation.
Cucumber has shallow roots, so “small meals, more often” is the principle for fertilizer and water management. When the plant reaches 25-30 leaves, pinch the growing point to promote the setting of second-crop cucumbers, and promptly remove old leaves, diseased leaves and curled leaves.
Harvest stage: During this period, fertilizer and water should follow the principle of light watering and frequent watering, and the amount of fertilizer applied should be light first and then heavy.
Depending on plant growth and harvest conditions, apply 2 kg of balanced macroelement fertilizer + 3 kg of high-potassium fertilizer + 5 kg of Sea Elf biostimulant per mu each time, preferably once every 10 days. According to actual conditions, foliar topdressing with 1% magnesium sulfate or 0.5% EDTA chelated magnesium can be carried out.
The complete set of greenhouse cucumber cultivation techniques has been shared with everyone in the above points. I hope this article is helpful to everyone, and I wish everyone good luck.