Radish
Raphanus sativus
Also known asSpring radish · European radish · Garden radish · Rabano
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 2–10 (winter low around -46°C)
- Frost
- frost hardy
- Season
- cool (spring/fall)
Growing systems
Root mass: moderate.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies | high | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
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 | 0.8 |
| vegetative | 2 | 1 | 2 | 1.8 |
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
The fastest root crop for hydroponic systems. Media beds or containers with 8–12 cm of loose substrate for standard salad radishes (deeper for daikon types). EC 1.2-2.0 mS/cm. pH 6.0-7.0. Temperature: 10–22°C (cool-season; above 25°C, roots become pithy, hollow, and excessively peppery). Moderate light (DLI 12-18 mol/m2/day). From seed to harvest: 22-30 days for standard salad radishes, making them the fastest root crop available. Direct seed (radishes don't transplant well). Thin to 3–5 cm spacing. Harvest when the root top is 2–3 cm diameter at the soil line; delay causes cracking, pithiness, and increasing heat. Succession plant every 2 weeks for continuous supply. The greens are edible and peppery; use in salads, pesto, or sauteed like turnip greens. Watermelon radish ('Red Meat') takes longer (50-60 days) but produces a stunning, Instagram-worthy cross-section. For aquaponics media beds, radishes are the ideal quick-gratification crop between longer-season plantings.