Turnip
Brassica rapa subsp. rapa
Also known as: White turnip, Garden turnip, Neep, Nabo
Quick facts
- Category
- roots bulbs
- Difficulty
- beginner
- Days to harvest
- 40 to 70 days
- Harvest type
- single harvest then replant
- Spacing
- 10 cm between plants
Environment
- Temperature
- 7–24°C
- pH
- 6 to 7
- EC (hydroponic)
- 1.4 to 2.2 mS/cm
- Daily light
- 13 to 18 mol/m²/day
Climate and zones
- USDA zones
- 2 to 10 (winter low around -46°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
Turnip works in:
- 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 (turnip works in the media listed below).
| Medium | pH effect | Water retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies by source | high | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Expanded clay pebbles (LECA) | neutral / inert | low | 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 | 2 | 1 | 3 | 1.8 |
Companion-growing notes
- Heavy uptake of potassium. Co-grown crops with the same demand will end up deficient even at "correct" EC. Plan around this in shared reservoirs.
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
One of the fastest root crops for hydroponic media beds. 8–12 cm of loose substrate. EC 1.5-2.5 mS/cm. pH 6.0-7.0. Temperature: 10–22°C (cool-season; above 25°C, roots become woody and pungent). Moderate light (DLI 12-18 mol/m2/day). From seed to harvest: 30-45 days for baby types ('Hakurei', 'Tokyo Cross'), 45-65 days for standard types. Direct seed and thin to 5–8 cm. Baby turnips are harvested when roots are 4–6 cm and eaten raw (sliced, with butter and sea salt, or in salads); the sweetness and tenderness of a well-grown baby turnip is a revelation for people who only know the strong, fibrous turnips of traditional cooking. The greens are harvestable throughout growth. Flea beetles are the main pest. For aquaponics growers, turnips offer the fastest root-crop gratification in any media bed.
Verified against: rhs-uk, university-of-florida-ifas. Last reviewed 2026-05-15.