About This Plant
Cucumber (Cucumis sativus) is a warm-season cucurbit and one of the most widely grown vegetables in hydroponic production worldwide. This vigorous, indeterminate vine thrives in high-light, high-humidity greenhouse environments, reaching 1.5-3 m when trained vertically on strings or trellises. Cucumber is uniquely potassium-dominant among hydroponic crops, requiring more K than N during flowering and fruiting. It responds exceptionally well to CO2 enrichment (+22% yield at 1000 ppm) and drip irrigation with rockwool or coco coir substrates. Seeds germinate rapidly (3-5 days at 25-30 C) and first harvest is achievable within 50-70 days from sowing. A well-managed plant produces 4-5 kg per production cycle at intermediate difficulty. Key challenges include powdery mildew, Pythium root rot in recirculating systems, and aphid-vectored viral diseases.
How to Grow Cucumber
Learn how to grow Cucumber from seed to harvest in 70 days. Intermediate difficulty. Complete nutrient guide, pH/EC requirements, and growing conditions for hydroponics, soil & greenhouse.
Backed by 30 peer-reviewed citations.
Nutrient Requirements by Growth Stage
Cucumber is a heavy-feeding cucurbit uniquely requiring more potassium than nitrogen during fruiting — one of few hydroponic crops with this characteristic. Begin seedlings at EC 1.0-1.5 with moderate N (100-150 ppm) and balanced K (150-200 ppm)…
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Growing Environments
Greenhouse is the primary commercial environment for cucumber, providing the controlled warmth, humidity, and light that this tropical crop requires. Indoor cultivation is fully viable with high-intensity lighting (DLI 25+, PPFD 430+) and temperature/humidity control — ideal for year-round production in any climate…
Temperature
Cucumber is a warm-season crop requiring consistent heat for rapid growth and fruit development. Seeds germinate from 16 C minimum to 35 C optimum, with emergence in 3-5 days at 25-30 C. Below 12 C, germination is negligible. For vegetative and reproductive growth, maintain 18-30 C with an optimal daily mean of 24 C (day 26 C, night 18-20 C). Temperatures above 35 C cause flower abortion and bitter fruit. Night temperatures below 15 C slow growth and reduce fruit set significantly. The narrow growth optimum (24 C mean) reflects cucumber's tropical origin — it has no frost tolerance whatsoever. Root-zone temperature of 20 C+ is critical for nutrient uptake, particularly phosphorus, which accumulates in roots without translocation below 20 C.
Humidity
Cucumber is a high-transpiration crop that thrives in moderate-to-high humidity. Maintain 60-80% relative humidity with an optimal target of 70% as a 24-hour average…
Light
Cucumber requires high light intensity for commercial yields. Target a DLI (daily light integral) of 20-30 mol/m2/d, with 25 mol/m2/d as an excellent mid-range target for fruiting crops…
Airflow
Maintain 0.3-1.0 m/s air velocity at canopy level. Minimum 0.3 m/s prevents stagnant microclimates that promote powdery and downy mildew, which are the most damaging diseases of greenhouse cucumber…
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Hydroponic System Compatibility
Drip irrigation with substrate is the global commercial standard for greenhouse cucumber (rated excellent) — rockwool slabs, coco coir, or perlite bags provide precise nutrient delivery, structural support for large plants, and optimal EC/pH control. DWC and ebb-flow are good alternatives providing adequate root…
Growing Media
Rockwool slabs are the undisputed industry standard for commercial greenhouse cucumber, offering excellent water retention (80% by volume), aeration (15-20% air), sterility, and structural support for plants bearing heavy fruit loads. Coco coir is increasingly adopted as a renewable, high-performance alternative with…
Container Specs
Use containers at least 30 cm in both depth and width per plant (approximately 15 L volume minimum). Research demonstrates significant yield reduction in containers below 12-15 L…
Training & Support
Training is not strictly required — cucumber is naturally a trailing vine that produces fruit when sprawling — but is strongly recommended for vining varieties due to 2-3x yield increase, improved fruit quality, reduced disease, and 70% space savings. Trellis (A-frame, flat panel, or lean-to) is the most common garden…
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Propagation
Cucumber is one of the easiest vegetables to propagate from seed — large seeds germinate rapidly with no pretreatment required. Sow 2-2.5 cm deep in moist growing medium at 25-30 C for fastest germination (3-4 days)…
Harvesting
Cucumber is an indeterminate crop producing fruit continuously once flowering begins, with the harvest period typically lasting 10-12 weeks. Harvest when fruits reach uniform length — 30-36 cm for European types (USDA minimum 28 cm), 13-20 cm for mini/Beit Alpha types — with firm texture, external glossiness, and no…
Planting Calendar
For temperate Northern Hemisphere climates (USDA zones 4-12): Start seeds indoors in March-April, 3-4 weeks before last frost date. Use large cells or peat pots — cucurbits are sensitive to root disturbance…
Common Issues
Cucumber is susceptible to fungal diseases, oomycete root rots, viral diseases, and arthropod pests in greenhouse and hydroponic systems. The five primary diseases are powdery mildew (Podosphaera xanthii — white colonies on leaves, managed with Bacillus subtilis or sulfur fungicides), downy mildew (Pseudoperonospora…
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