Bush beans
Phaseolus vulgaris
Also known asGreen beans · String beans · Snap beans · French beans · Haricots verts
Environment
The bounded range this crop tolerates. Strict on light; outside the DLI band, yields drop sharply.
Climate and zones
- USDA zones
- 10–13 (winter low around -1°C)
- Frost
- frost sensitive (dies at first frost)
- Season
- warm (summer, frost-sensitive)
Growing systems
Root mass: moderate.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Perlite (Expanded volcanic glass) | neutral / inert | very low | low |
| Soil-based mix (Potting soil) | varies | high | high |
Nutrient demand by stage
NPK ratios are relative weights. EC targets shift through the plant's life.
| Stage | N | P | K | EC (mS/cm) |
|---|---|---|---|---|
| seedling | 1 | 1 | 1 | 1 |
| vegetative | 2 | 1 | 2 | 1.7 |
| flowering | 1 | 2 | 3 | 2 |
| fruiting | 1 | 2 | 4 | 2 |
Companion-growing notes
- Heavy uptake of potassium. Co-grown crops with the same demand will end up deficient even at "correct" EC.
- High transpiration. Regular reservoir top-ups needed during fruiting.
Aquaponics suitability
Compatible
Fish waste provides enough nitrogen for healthy growth. Supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.
Care notes
A reasonably good hydroponic crop, and the bush habit means no trellis. Hold EC around 1.5-2.2 mS/cm and pH 6.0-6.5. It is warm-season, best at 18–28°C, with growth stalling below 15°C. Give moderate to high light, 18-25 mol/m2/day. Deep water culture, media beds and Dutch bucket all work. Because rhizobia are usually absent in soilless culture, the plants depend on the nutrient solution for nitrogen rather than fixation. First harvest comes 50 to 65 days from seed. Pick snap beans while pods are pencil-thick and snap cleanly; left too long they turn tough and stringy. Bush beans set most pods in a two to three week window then taper off, so sow every three to four weeks for a steady supply. Each plant gives roughly 200–400 g of pods. Watch for bean beetles, powdery mildew (improve airflow), and blossom drop from heat above 32°C. In aquaponics they grow well in media beds alongside leafy greens.