Borage
Borago officinalis
Also known asStarflower · Bee bush · Cool tankard · Borraja · Bourrache
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 3–10 (winter low around -40°C)
- Frost
- tolerates light frost
- 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 | 0.6 |
| vegetative | 2 | 1 | 2 | 1.3 |
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 productive hydroponic herb grown primarily for its edible flowers. EC 1.2-2.0 mS/cm. pH 5.5-7.0. Temperature: 15–25°C (cool-season annual; heat above 28°C causes rapid bolting and reduced flower quality). Moderate to high light (DLI 14-20 mol/m2/day). Plants grow 40–80 cm tall and spread significantly; space generously. DWC or media bed systems work best because the root system is substantial. From seed to first flowers: 6-8 weeks. Each plant produces flowers continuously for 4-8 weeks before declining. The flowers are the primary harvest: pick individual flowers daily as they open, using them fresh or frozen. Frozen borage flowers in ice cubes are a popular cocktail garnish. Young leaves (before the hairs become prickly) can be added to salads or cooked like spinach. The hairy stems and older leaves are unpleasant to eat raw. Borage self-seeds aggressively in outdoor settings; in hydroponic systems, this isn't a concern. A rewarding specialty crop for growers who value edible flowers for culinary presentation or cocktail garnish.