Rosemary
Salvia rosmarinus
Also known asGarden rosemary · Romarin · Romero
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 7–10 (winter low around -18°C)
- Frost
- tolerates light 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 |
| 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 |
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 long-lived perennial herb for container or hydroponic growing. Use a container (15 L) with very well-drained media (perlite, pumice or expanded clay), since rosemary dies in waterlogged conditions. EC 1.0-1.6 mS/cm (a light feeder). pH 6.0-7.5 (tolerates slightly alkaline). Temperature: 10–30°C (Mediterranean; cold-hardy to about zone 7-8 depending on variety). Full sun (DLI 18-30 mol/m2/day). Growth is slow to moderate. Harvest by cutting stem tips (10–15 cm); the plant branches freely when pruned, but because it is woody it will not regrow from bare, leafless wood, so always cut above green growth. To dry, strip leaves from the stems and dry at 35–40°C or hang in bundles; dried rosemary holds excellent flavour for over a year. Propagate by semi-hardwood cuttings taken in summer (rooting in 3-6 weeks in moist perlite); seed is possible but slow with poor germination. Overwatering and poor drainage are the main causes of failure, and rosemary needs drier conditions than basil or mint.