Hyssop
Hyssopus officinalis
Also known as: True hyssop, Common hyssop, Hisopo, Isop
Quick facts
- Category
- herbs woody
- Difficulty
- intermediate
- Days to harvest
- 75 to 100 days
- Harvest type
- cut leaves, plant regrows for repeated harvests
- Spacing
- 45 cm between plants
Environment
- Temperature
- 5–28°C
- pH
- 6.5 to 8
- EC (hydroponic)
- 1 to 1.6 mS/cm
- Daily light
- 16 to 22 mol/m²/day
Climate and zones
- USDA zones
- 4 to 9 (winter low around -34°C or warmer)
- Frost tolerance
- very hardy (survives deep cold)
- Season
- warm (summer crops, frost-sensitive)
Viable growing environments:
- outdoor year-round (in zone)
- outdoor in growing season (annual)
- unheated greenhouse / hoop house
- indoor (heated home)
USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.
Growing systems
Hyssop works in:
- drip / Dutch buckets
- media bed (ebb and flow)
- wicking bed
- soil bed
Growing media
The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (hyssop works in the media listed below).
| Medium | pH effect | Water 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 |
| Soil-based mix (Potting soil) | varies by source | high | high |
Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.
Nutrient demand by stage
NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.
| Stage | N | P | K | EC target (mS/cm) |
|---|---|---|---|---|
| seedling | 1 | 1 | 1 | 0.6 |
| vegetative | 2 | 1 | 2 | 1.3 |
Aquaponics suitability
Not recommended for pure aquaponics. Fish waste alone doesn't provide enough of the nutrients this crop demands (typically potassium, calcium, or boron). It can be grown in a hybrid system where the reservoir is supplemented with hydroponic-style nutrients, but expect to dose actively.
Care notes
An easy, long-lived perennial herb for hydroponic or container growing. EC 1.0-1.8 mS/cm. pH 6.0-8.0 (tolerates alkaline conditions). Temperature: 10–28°C (Mediterranean; cold-hardy to USDA zone 4). Full sun (DLI 16-22 mol/m2/day). Well-drained media (the plant is drought-tolerant and dislikes waterlogged roots). Growth is moderate. Harvest stem tips with leaves and flower buds. The flowers are edible, beautiful blue-violet, and make an attractive garnish. For tea, dry leaves and flower tops at 35–40°C. Use sparingly in cooking because the flavor is potent: a few leaves in a pot of white beans, or chopped fine as part of a herb blend for lamb. Propagation by stem cuttings, division, or seed. Prune in spring to maintain compact shape and prevent the woody base from becoming bare. The plant attracts pollinators vigorously; in a greenhouse, flowering hyssop helps with pollination of nearby fruiting crops. A low-maintenance, long-lived herb that earns its space through versatility and pollinator support.
Verified against: rhs-uk, herb-society-of-america, u-of-bologna-italy. Last reviewed 2026-05-15.