Bell pepper
Capsicum annuum
Also known asSweet pepper · Capsicum · Paprika (fresh, EU usage) · Pimento · Bell capsicum
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: heavy. Thin-channel systems can't hold this crop.
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 |
| Rockwool (Mineral wool) | alkaline until pre-soaked | very high | 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 | 3 | 1 | 2 | 2 |
| flowering | 2 | 2 | 3 | 2.3 |
| fruiting | 1 | 2 | 4 | 2.6 |
Companion-growing notes
- Heavy uptake of potassium, calcium. 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 premier hydroponic crop with mature commercial protocols. Dutch bucket, drip-to-waste or rockwool slab systems are the commercial standard. Hold EC around 1.8-2.8 mS/cm, raising it as plants mature into heavy fruiting, and pH 5.5-6.5. Run 21–28°C by day and 16–18°C at night, since the day-night swing helps fruit set. Light demand is high, on the order of 22-30 mol/m2/day, to build thick walls and large fruit. Train to two to four leaders using the Spanish or Dutch method, keeping the main stems at the first fork and removing other suckers, then support with string or stakes. Steady calcium prevents blossom end rot, and extra potassium during fruiting improves colour and wall thickness. Green-stage fruit is ready about 60 to 75 days from transplant, red about 80 to 100. Each plant carries 8 to 15 fruits per cycle. Watch for blossom drop from temperature extremes or poor pollination (shake plants gently to release pollen indoors), plus aphids and thrips. Bell peppers are one of the highest-value hydroponic vegetables.
Notable varieties
| Cultivar | Type | Origin | Days | Size | Notes |
|---|---|---|---|---|---|
| California Wonder | open pollinated | 75 | 200 g | Pre-1928 open-pollinated standard. Blocky four-lobed green-to-red fruit. Tolerates a wide climate range; the default bell pepper for most US home growers. Average yield, average flavor, very reliable. | |
| King of the North | open pollinated | 70 | 180 g | Cool-climate selection. Sets fruit at lower temperatures than most bells; produces useful yields in zones 4-6 where California Wonder struggles. Green-to-red. | |
| Big Red | hybrid | Burpee | 75 | 300 g | F1 producing very large 8-10cm thick-walled fruit. Higher yield than open-pollinated bells. Green-to-red. Disease resistance to Tobacco Mosaic Virus. |
| Lipstick | open pollinated | 70 | 150 g | Pimento-style sweet pepper. Smaller than bells, thicker walls, sweeter flavor. Ripens dependably red even in cooler zones. Excellent fresh or roasted. | |
| Jimmy Nardello | heirloom | 80 | 90 g | Italian frying pepper, not a bell despite often being grouped with them. Long thin red fruit, very sweet when fully ripe. Slow Food Ark of Taste listed; one of the best frying peppers in any climate. |