Cucumbers
High-water, high-light warm-season crop. Cucumbers are vigorous growers that produce rapidly once established. Good fit for the West Zone with its long wall of shelving and overhead grow lights.
Optimal Conditions
| Parameter | Range | Notes |
|---|---|---|
| Day temperature | 75-82°F | Sensitive to cold. Below 60°F = growth stops. |
| Night temperature | 65-70°F | Warmer nights than lettuce |
| VPD | 0.8-1.2 kPa | High transpiration rate — sensitive to dry air |
| DLI | 20-25 mol/m²/d | Heavy light requirement |
| pH (hydro) | 5.5-6.0 | Slightly acidic |
| EC | 1.7-2.5 mS/cm | Moderate-heavy feeder |
| Photoperiod | 14-18 hours | Day-neutral for most greenhouse varieties |
Varieties for This Greenhouse
| Variety | Type | Length | Days | Pollination | Notes |
|---|---|---|---|---|---|
| Beit Alpha | Mini/snacking | 4-6” | 50-55 | Parthenocarpic | Best for greenhouse — no pollination needed |
| English (telegraph) | Long | 12-14” | 55-65 | Parthenocarpic | Classic greenhouse cucumber |
| Picolino | Mini | 3-4” | 50-55 | Parthenocarpic | Snacking size, prolific |
| Marketmore | Slicing | 8-9” | 58-68 | Bee-pollinated | Outdoor type, less ideal for greenhouse |
Recommendation: Beit Alpha or Picolino. Parthenocarpic varieties are essential in a greenhouse — no bees required.
Zone Recommendation
Primary: West Zone shelving or floor
The west zone offers moderate temperatures with strong afternoon light from the longest wall. Cucumbers need more light than lettuce but less heat tolerance than peppers — the west zone is the sweet spot.
Hydro option: Cucumbers can grow in the East Zone hydro system but their vigorous vining habit and large leaves create shading issues for neighboring crops. Better as dedicated plants in the west zone.
Growing Notes
- Vertical growing: Train up a trellis or string to save floor space. A single plant can produce 20+ cucumbers in a season when trained vertically.
- Water demand: Cucumbers are 95% water. Consistent, heavy watering essential.
- Harvest frequently: Pick cucumbers small for best quality. Overripe fruit signals the plant to stop producing.
- Sensitive to cold: More cold-sensitive than tomatoes or peppers. Keep away from the vent opening on cold nights.
Longmont-Specific Notes
- Dry air challenge: Cucumbers are sensitive to low humidity. VPD above 1.5 kPa causes leaf curl. Hot spring afternoons (VPD 2.0+) will stress cucumbers.
- Short outdoor season: Longmont’s frost-free window (100 days) barely allows one outdoor cucumber crop. The greenhouse provides 3-4 full cycles per year.
Economics
| Metric | Value |
|---|---|
| Grocery price | $1-2 per cucumber |
| Greenhouse yield | 15-25 fruit per plant |
| Cycle time | 50-70 days |
| Value per plant per cycle | $15-50 |
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