Salsify
Tragopogon porrifolius
Also known as: Oyster plant, Vegetable oyster, Common salsify, Goatsbeard, Purple salsify
Quick facts
- Category
- roots bulbs
- Difficulty
- intermediate
- Days to harvest
- 120 to 150 days
- Harvest type
- single harvest then replant
- Spacing
- 10 cm between plants
Environment
- Temperature
- 7–24°C
- pH
- 6 to 7.5
- EC (hydroponic)
- 1 to 1.6 mS/cm
- Daily light
- 14 to 20 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)
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
Salsify works in:
- soil bed
Root mass is heavy - thin-channel systems (NFT, vertical towers) can't hold this crop mechanically, hence the system list above.
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 (salsify works in the media listed below).
| Medium | pH effect | Water retention | Bacterial surface |
|---|---|---|---|
| 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 | 1 | 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
A deep-rooted crop requiring 30 cm of loose, obstacle-free growing medium (similar to parsnip or long daikon). Media beds or very tall containers with fine-grained, stone-free substrate. EC 1.5-2.0 mS/cm. pH 6.0-7.0. Temperature: 12–22°C (cool-season). Moderate light (DLI 12-18 mol/m2/day). Long season: 110-130 days from seed. Direct seed (the taproot doesn't survive transplanting). Thin to 8–10 cm spacing. Seed viability declines quickly; use fresh seed. Harvest by loosening the media deeply and pulling the fragile root carefully (they snap easily). Process quickly after harvest: peel, drop immediately into acidulated water (water with lemon juice or vinegar) to prevent browning. For roasted salsify: toss peeled, cut pieces with olive oil, salt, and thyme, roast at 200°C until golden and caramelized. The flavor is delicate, sweet, and unlike any other common vegetable.
Verified against: rhs-uk, u-of-minnesota-extension, gardeners-world-uk. Last reviewed 2026-05-15.