Parsley
Petroselinum crispum
Also known as: Flat-leaf parsley, Italian parsley, Curly parsley, Persil
Quick facts
- Category
- herbs soft
- Difficulty
- beginner
- Days to harvest
- 70 to 90 days
- Harvest type
- cut leaves, plant regrows for repeated harvests
- Spacing
- 20 cm between plants
Environment
- Temperature
- 10–24°C
- pH
- 5.5 to 6.5
- EC (hydroponic)
- 1 to 1.6 mS/cm
- Daily light
- 12 to 18 mol/m²/day
Climate and zones
- USDA zones
- 4 to 9 (winter low around -34°C or warmer)
- Frost tolerance
- frost hardy (handles regular frost)
- Season
- cool (spring and fall crops)
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
Parsley works in:
- deep water culture (rafts)
- NFT channels
- 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 (parsley works in the media listed below).
| Medium | pH effect | Water retention | Bacterial surface |
|---|---|---|---|
| Rockwool (Mineral wool) | alkaline until pre-soaked | very high | low |
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Net pot, no medium (Bare-root) | - | - | - |
| 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
A staple hydroponic herb with consistent demand. EC 1.0-2.0 mS/cm. pH 5.5-7.0. Temperature: 10–25°C (cool to moderate; tolerates heat better than cilantro but bolts in sustained temperatures above 28°C). Moderate light (DLI 12-18 mol/m2/day). NFT, DWC, Kratky, or media bed systems. Seed germination is slow (2-3 weeks) and erratic; soaking seeds overnight in warm water improves germination speed. From seed to first harvest: 8-10 weeks (one of the slower herbs from seed). Harvest outer stems at the base; the plant continues producing from the center for months. Flat-leaf varieties ('Giant of Italy', 'Titan') are preferred for commercial hydroponic production because of their stronger flavor and faster regrowth after cutting. Parsley is biennial: in its second year, it flowers, sets seed, and dies. For continuous production, succession plant annually. The herb is relatively pest-free. For commercial hydroponic herb growers, Italian flat-leaf parsley is one of the core crops alongside basil, cilantro, and mint.
Verified against: rhs-uk. Last reviewed 2026-05-15.