Sorrel
Rumex acetosa
Also known as: Garden sorrel, Common sorrel, Spinach dock, Sour dock
Quick facts
- Category
- leafy greens
- Difficulty
- beginner
- Days to harvest
- 60 to 90 days
- Harvest type
- cut leaves, plant regrows for repeated harvests
- Spacing
- 25 cm between plants
Environment
- Temperature
- 10–24°C
- pH
- 5.5 to 7
- EC (hydroponic)
- 1.2 to 2 mS/cm
- Daily light
- 12 to 18 mol/m²/day
Climate and zones
- USDA zones
- 3 to 9 (winter low around -40°C or warmer)
- Frost tolerance
- very hardy (survives deep cold)
- 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
Sorrel 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 (sorrel 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 | 0.7 |
| vegetative | 3 | 1 | 2 | 1.5 |
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, long-lived perennial herb/green for hydroponic systems. EC 1.0-2.0 mS/cm. pH 5.5-7.0. Temperature: 10–25°C (cool to moderate; the flavor is mildest in cool weather). Low to moderate light (DLI 10-18 mol/m2/day; tolerates partial shade). Any hydroponic system works. From seed to first harvest: 6-8 weeks. From division of existing clump: immediately harvestable. Harvest young leaves by cutting at the base; the plant regrows continuously. The tart, lemony flavor adds brightness to dishes without adding liquid (unlike lemon juice). For sorrel soup: sweat a large quantity of sorrel in butter until it melts into a puree (it turns olive-brown, which is normal), add stock and cream, season. The soup can be served hot or cold. Remove flower stalks to keep the plant producing tender leaves rather than going to seed. A single sorrel plant provides more tart greens than a household typically needs.
Verified against: rhs-uk. Last reviewed 2026-05-15.