Marjoram
Origanum majorana
Also known as: Sweet marjoram, Garden marjoram, Knotted marjoram
Quick facts
- Category
- herbs woody
- Difficulty
- beginner
- Days to harvest
- 75 to 120 days
- Harvest type
- cut leaves, plant regrows for repeated harvests
- Spacing
- 25 cm between plants
Environment
- Temperature
- 15–28°C
- pH
- 6 to 7.5
- EC (hydroponic)
- 1.2 to 1.8 mS/cm
- Daily light
- 16 to 24 mol/m²/day
Climate and zones
- USDA zones
- 7 to 10 (winter low around -18°C or warmer)
- Frost tolerance
- tolerates light frost
- Season
- warm (summer crops, frost-sensitive)
Viable growing environments:
- outdoor year-round (in zone)
- outdoor in growing season (annual)
- unheated greenhouse / hoop house
- heated greenhouse
- indoor (heated home)
- indoor hydroponics under grow lights
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
Marjoram works in:
- media bed (ebb and flow)
- wicking bed
- soil bed
- drip / Dutch buckets
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 (marjoram 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 |
| 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 | 1.4 |
Aquaponics suitability
Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.
Care notes
An easy, compact herb for hydroponic growing. EC 1.0-1.8 mS/cm. pH 6.0-8.0 (tolerates slightly alkaline conditions). Temperature: 15–28°C (prefers moderate warmth; frost kills the plant, though it survives mild cold). Full sun (DLI 16-22 mol/m2/day). NFT, DWC, Kratky, or container systems. From seed to first harvest: 6-8 weeks. Harvest by cutting stem tips; the plant branches freely when pinched, becoming bushier with each cut. The flavor is most concentrated just before flowering. For drying: cut whole stems, hang in bundles, and strip leaves once dry, or dehydrate at 35–40°C. Marjoram is one of the few herbs that is arguably better dried than fresh for certain uses (it concentrates and rounds the flavor). The plant flowers readily; the small flower clusters are also edible and aromatic. In a mixed herb garden, marjoram's compact habit and low water needs make it compatible with rosemary, thyme, and sage. For German or Austrian cooking enthusiasts, marjoram is an essential herb that many American cooks overlook.
Verified against: rhs-uk. Last reviewed 2026-05-15.