Protected Cultivation Techniques of Cucumber

A. Introduction

• Cucumber (Cucumis sativus L.) is one of the most important high-value vegetable crops grown under protected cultivation.
• Popular for salad, pickles, and fresh consumption.
• Requires controlled environment for uniform fruiting, year-round production, and higher yield.
• Commonly cultivated in greenhouses, polyhouses, and net houses.
• Parthenocarpic cucumber hybrids are most suitable for protected cultivation.

B. Importance of Protected Cultivation in Cucumber

• Allows off-season and year-round production.
• Protects from excessive rainfall, frost, hail, and wind.
• Ensures uniform fruit quality (straight, green, tender cucumbers).
• Reduces pest and disease pressure.
• Increases productivity (up to 150–200 t/ha).
• High economic returns due to continuous market demand.

C. Climate and Environmental Requirements

• Temperature: Optimum 20–30°C; growth slows below 15°C.
• Relative Humidity: 60–70% is ideal.
• Light: Requires medium light intensity; excess shading reduces yield.
• CO₂: Enrichment up to 800–1000 ppm improves fruit set and yield.
• Ventilation: Essential to regulate humidity and temperature, and reduce fungal disease incidence.

D. Suitable Varieties/Hybrids for Protected Cultivation

• Parthenocarpic hybrids are preferred because they set fruits without pollination.
• Common commercial hybrids:
• European types: Claudine, Carmen, Kalunga, Sultan.
• Japanese/Korean types: Shourabh, Malini, Sonali.
• Nepal (Krishi Diary 2081 recommended): Neeraj, Malini, NS 404, Sonali, and other parthenocarpic hybrids tested under protected conditions.

E. Growing Structures

• Naturally ventilated polyhouse is widely used.
• Greenhouse with controlled environment (temperature, RH, CO₂, and irrigation) preferred for commercial production.
• Raised beds with drip irrigation and plastic mulching commonly adopted.

F. Propagation and Planting

• Propagated through seeds of hybrids.
• Sowing is done in protrays with cocopeat media.
• Seedlings are transplanted at 2–3 leaf stage (about 15–20 days old).
• Spacing: 1.5–2.0 m between rows, 45–60 cm between plants; about 2.5–3 plants/m².
• Raised beds (20–30 cm height, 1 m width) ensure good drainage.

G. Soil/Growing Media Preparation

• Soil must be well-drained, sandy loam with pH 5.5–6.8.
• Soil sterilization (formalin, solarization, or steaming) is essential to avoid soil-borne diseases.
• For soilless cultivation: Cocopeat, Perlite, Vermiculite, Rockwool are used as media.

H. Nutrient and Irrigation Management

• Fertigation through drip irrigation is the standard practice.
• Basal application: Organic manure 20–25 t/ha.
• Fertigation schedule (kg/ha/year): N: 200–250, P₂O₅: 100–120 and K₂O: 250–300
• Micronutrients: Foliar sprays of Zn, B, Fe, Mn as required.
• Irrigation: Frequent light irrigation to maintain uniform soil moisture. Avoid waterlogging.

I. Crop Management Practices

• Training: Vertical single-stem training to wires (2–2.5 m height). Side shoots pruned to maintain single stem.
• Pruning: Removal of lower leaves, side suckers, and unproductive laterals to improve ventilation and light penetration.
• Staking: Nylon ropes or wires used to support vines.
• Pollination: Not required for parthenocarpic hybrids; in non-parthenocarpic types, bumble bees are introduced.
• Mulching: Black polythene mulch conserves moisture, suppresses weeds, and maintains soil temperature.

J. Use of Plant Growth Regulators (PGRs)

• GA₃ (10–20 ppm) promotes elongation of vines.
• Ethrel (200 ppm) encourages female flower formation in monoecious varieties.
• PGRs generally not required for parthenocarpic hybrids.

K. Pest and Disease Management

a. Pests:

• Aphids, whiteflies, thrips, mites, leaf miners.
• Control: Sticky traps, neem oil, systemic insecticides (imidacloprid, spiromesifen).

b. Diseases:

• Powdery mildew, downy mildew, fusarium wilt, anthracnose, cucumber mosaic virus.
• Control: Resistant hybrids, crop rotation, fungicide sprays (carbendazim, mancozeb), IPM strategies.

c. Integrated approach:

• Soil sterilization + biological agents (Trichoderma, Pseudomonas) + proper ventilation + drip fertigation + minimal pesticide use.

d. Disorders:

• Pointed end of the fruits (black rot or slow growth)
• Bent fruits (slow fruit growth)
• Club formed fruits (stress)
• Inversed fruits (even temperature)
• Cork strips (usually dew on the fruits)
• Black fruits (deficiency of carbohydrates)
• Light fruits (low salinity and low light to the fruits)
• Grey fruits (too much Si)
• Light tips and inversed (because of strong growth)

e. Harvesting and Yield

• First harvest: 45–50 days after planting.
• Harvesting interval: Every 2–3 days for uniform size and quality.
• Fruits should be harvested at tender stage (20–25 cm length).
• Average yield: 8–10 kg/plant; 120–150 t/ha under good management.

f. Post-Harvest Management

• Harvested fruits are graded based on size, shape, and color.
• Packed in plastic crates or cartons for transport.
• Stored at 10–12°C with 85–90% RH for 10–14 days.