How to Grow Greenhouse Cucumbers? A Detailed Explanation of 5 Key Cultivation Techniques

Greenhouse cucumbers have the characteristic of delayed cultivation, which allows cucumbers to reach the market during the vegetable off-season, with both social and economic benefits being very significant. Below is an introduction to the 5 key cultivation techniques for greenhouse cucumbers.

I. Variety Selection

For early spring cultivation, choose varieties that are early-maturing, highly cold-tolerant, and fast in fruit development.

II. Raising Strong Seedlings

Before sowing cucumbers, the seeds must be disinfected, usually by soaking in warm water. Soak cucumber seeds in hot water at 55°C for 10-15 minutes. When the water temperature drops to 30°C, stop stirring and continue soaking for 4-6 hours, then wrap them in wet gauze for germination, with the germination temperature generally at 28-30°C.

For early spring seedlings, the seedling age is about 35 days. Before transplanting, carry out adequate low-temperature hardening, and raise seedlings in nutrient pots or plug trays. (For autumn delayed cultivation, direct sowing can be used. The standard for strong seedlings is: 3-4 true leaves, larger leaves that are dark green, intact cotyledons that are thick and plump, plant height of about 15 cm, hypocotyl not exceeding 6 cm, stem diameter of 5-6 mm, and no pests or diseases.)

III. Timely Transplanting

Cover the greenhouse film early and raise the temperature. Cover the greenhouse film 20-30 days before transplanting. When the previous crop is finished, disinfect the greenhouse. You can spray the posts and greenhouse film with trisodium phosphate or sodium hypochlorite, or fumigate with smoke agents such as chlorothalonil. After the soil thaws, plow the land in time and apply sufficient base fertilizer, mainly organic fertilizer, and cultivate on high ridges with plastic film mulch. Transplant as early as possible while ensuring the seedlings are not damaged by freezing, with the 10 cm soil temperature inside the greenhouse above 12°C and the lowest nighttime temperature not lower than 5°C. Plant at moderate density, about 4000 plants per mu, and transplant moderately shallowly.

IV. Field Management

1. Temperature management: For early spring cultivation, cucumbers need heat preservation and cold protection in the early stage. Generally, no ventilation is given before the seedling recovery stage, and care should be taken to keep the nighttime temperature above 15°C. Seedling recovery takes about 7 days. Take various measures to increase the nighttime temperature and promote seedling recovery. From after seedling recovery to the root fruit setting stage, about 20 days, appropriately control the temperature: 20-25°C during the day and 12-16°C at night to prevent excessive vegetative growth. During the full fruiting period, appropriately control the temperature: 25-30°C during the day and 16-18°C at night.

2. Fertilizer and water management and intertillage: In early spring cultivation, the soil temperature is relatively low, so the transplanting water should be appropriately reduced. After the seedling recovery water, carry out intertillage and moderately restrain seedling growth. After the root cucumber is harvested, water once every 5 days. Watering is best done on clear mornings. After sudden clearing following summer rainstorms, water once, and after watering, ventilate promptly to reduce air humidity inside the greenhouse.

From transplanting to root cucumber harvest, topdress 1-2 times; during the peak fruiting period, once every 7-10 days. Alternate diammonium phosphate and ammonium nitrate, and apply them with irrigation water.

3. Vine hanging and pruning: When cucumbers grow to 5 nodes, promptly hang the vines or set up trellises. After that, wind or tie the vines once every 2-3 days, and promptly remove all side branches and tendrils. When the vines approach the greenhouse film, pinch off the tips or twist the tips to control growth, and promptly remove diseased and old lower leaves.

V. Pest and Disease Control

The main diseases include cucumber downy mildew and powdery mildew, and the pests include aphids, whiteflies, and leafminers. Strengthen fertilizer and water management, apply more phosphorus and potassium fertilizer, improve the plants' disease resistance, and pay attention to greenhouse ventilation, light transmission, and humidity reduction to avoid the occurrence of pests and diseases. In the early stage of pest and disease occurrence, effective chemical control measures should be taken to control them, so as to extend the cucumber harvesting period and achieve the goal of increasing yield and income.

1. Downy mildew control: Spray with 72.2% Propamocarb aqueous solution at 800 times dilution, or 58% Ridomil wettable powder at 500 times dilution, or 64% Sandofan wettable powder at 400 times dilution, once every 7-10 days, for 2-3 consecutive applications. If the greenhouse humidity is high, use 45% chlorothalonil smoke agent, 250 g per mu, place it at 4-5 points inside the greenhouse, ignite with a smoldering flame, close the greenhouse and fumigate overnight, or use 5% chlorothalonil dust at 1000 g per mu, close the greenhouse overnight, ventilate in the morning, once every 7 days.

2. Powdery mildew control: To reduce greenhouse humidity, use 45% chlorothalonil smoke agent at 250 g per mu, place it in several spots and ignite, seal and fumigate overnight; in the early stage of disease occurrence, spray with 20% triadimefon at 2000 times dilution for control, or spray with 2% Wuyimycin aqueous solution at 200 times dilution, 20% polyoxin at 200 times dilution, 12.5% Sibao wettable powder at 2000 times dilution, and other agents. Spray once every 7 days, for 2-3 consecutive applications.

3. Leafminer control: A combination of yellow sticky board trapping of adults and chemical control can be adopted. Spray with 1.8% Abamectin emulsifiable concentrate at 3000 times dilution, or 20% Banqianjing at 1500 times dilution, once every 7 days, for 3-4 consecutive sprays.

4. Aphid and whitefly control: A combination of yellow sticky board trapping of adults and chemical control can be adopted. Use 30% Yashiyaxunjing smoke agent at 420 g per mu for smoke control, or spray with 25% Actara water-dispersible granules at 3000 times dilution, once every 7 days, for 3-4 consecutive applications, with good control results.