Rue
Ruta graveolens
Also known asCommon rue · Garden rue · Herb of grace · Ruda · Pixie
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 5–10 (winter low around -29°C)
- Frost
- very hardy (survives deep cold)
- Season
- warm (summer, frost-sensitive)
Growing systems
Root mass: moderate.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| 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 | 0.6 |
| vegetative | 2 | 1 | 2 | 1.2 |
Companion-growing notes
- Releases root compounds that can inhibit other crops in a shared reservoir.
Aquaponics suitability
Not recommended
Fish waste alone doesn't supply enough of what this crop demands. Grows in hybrid systems with supplemental dosing, but expect active management.
Care notes
A niche herb for experienced growers interested in historical or Ethiopian cuisine. Use a container (10 L) with well-drained media. EC 1.0-1.5 mS/cm (a very light feeder). pH 6.0-8.0 (tolerates alkaline conditions). Temperature: 15–28°C (Mediterranean; cold-hardy to about zone 4-5). Full sun (DLI 16-24 mol/m2/day). The plant is low-maintenance once established. Harvest leaves sparingly, since the flavour is intense and a single leaf is usually enough for a dish or drink, and use rue only in tiny amounts because it is toxic in quantity and acts as an abortifacient, so it should be avoided in pregnancy. Handle with gloves, especially in sun, because the psoralen furanocoumarins in the sap cause painful phytophotodermatitis blisters on UV-exposed skin, the same reaction caused by wild parsnip and giant hogweed; if sap contacts skin, wash the area at once and keep it out of sunlight for a couple of days. The attractive blue-green foliage makes rue a valued ornamental despite the hazard.