About This Plant
Turnip (Brassica rapa) is a fast-growing, cool-season Brassicaceae root vegetable prized for both its swollen white-and-purple hypocotyl 'root' and its edible peppery greens. A dual-purpose crop, it matures in roughly 40-60 days (about 55 days for a medium root) and is direct-sown rather than transplanted, since a disturbed taproot forks. It grows best at cool 10-24C temperatures - heat and long days trigger bolting and woody, bitter roots - and feeds as a low-nitrogen, potassium-and-phosphorus-forward root crop, distinct from the high-nitrogen fertility of turnip greens. Boron is critical: deficiency causes irreversible internal 'brown heart'. In soilless culture it suits substrate systems (ebb-and-flow, drip) that anchor the swelling root rather than bare-root DWC or NFT. Harvest roots at 5-8 cm diameter before they turn pithy.
How to Grow Turnip
Learn how to grow Turnip from seed to harvest in 55 days. Beginner difficulty. Complete nutrient guide, pH/EC requirements, and growing conditions for soil & container.
Sources cited: 35.
Nutrient Requirements by Growth Stage
Turnip feeds as a low-nitrogen, phosphorus-and-potassium-forward root crop - the opposite of high-nitrogen turnip-greens fertility, which is dosed at 175-250 lb N/acre versus 40-60 for roots. No turnip-specific hydroponic stage-ppm recipe exists, so the per-stage solution values below merge peer-reviewed…
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Growing Environments
Turnip adapts to indoor, outdoor, greenhouse and container culture. It is a classic cool-season outdoor bed crop for spring and autumn, and grows well in containers at least 20-25 cm deep thanks to its compact root system…
Temperature
Turnip is a cool-season Brassica whose eating quality collapses in heat, so hold growing temperatures around 10-24C with roughly 18C optimal for steady root and leaf development. Sustained warmth above ~24-27C, especially under long days, turns roots woody and pungent and pushes plants toward premature bolting. Germinate over a wide band: turnip sprouts in 1-2 days in warm soil (optimum near 29C/85F) but takes about 10 days in cool spring soil, with cardinal limits near 4C minimum and 40C maximum. In controlled hydroponic culture Shadd et al. grew turnip to harvest at 22-23C. A light frost close to harvest sweetens roots by converting stored starch to sugars.
Humidity
Hold relative humidity around 55-65% (acceptable 50-70%); the controlled turnip study ran at 55-60% RH through harvest. Moderate humidity with active air movement supports the transpiration that carries calcium and boron into the developing root and leaves, while sustained humidity above ~70% with stagnant air raises…
Light
Target a daily light integral near 15 mol/m2/day delivered over about a 16-hour photoperiod at roughly 260 umol/m2/s canopy PPFD - enough to drive both leaf canopy and root bulking in a fast crop (260 umol/m2/s over 16 h computes to DLI ~15, so the three light values are internally consistent). Do not extend the…
Airflow
Provide steady horizontal air movement across the canopy, roughly 0.3-1.0 m/s. Active airflow keeps leaf surfaces dry to suppress the Brassica foliar diseases turnip is prone to (downy mildew, white rust) and drives the transpiration stream that moves calcium and boron into the tissue, helping prevent tip burn on…
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Hydroponic System Compatibility
Turnip is a storage-root crop, which constrains soilless system choice more than a leafy green does. Substrate-based systems that physically anchor and give room to the swelling hypocotyl work best - ebb-and-flow (flood-and-drain) and drip through a deep media bed of coco-coir/perlite are the recommended methods…
Growing Media
Turnip needs a deep, loose, free-draining medium so the root can swell without obstruction - at least 20-25 cm of fine substrate. A coco-coir and perlite blend (about 70:30) is the preferred hydroponic medium, matching the substrate used to grow turnip to harvest in vertical culture; it holds moisture while draining…
Container Specs
Turnip grows well in containers given its compact root system, but the container must be deep enough for the root to bulk: provide at least 20-25 cm depth for full-size main-crop roots (20 cm suffices for baby turnips), with reliable drainage. Space plants about 7.5-10 cm apart; a 30 cm (12 in) pot holds ~4-6 turnips…
Training & Support
Turnip needs no trellis, stake or training - it is a low-growing root vegetable with compact basal foliage (20-40 cm tall), and the edible swollen root develops at and just below the medium surface. The only relevant practice is correct spacing and thinning, which keeps foliage open for airflow and gives each root…
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Propagation
Grow turnip from seed only, by direct sowing - there is no cutting or vegetative propagation, and transplanting is avoided because a disturbed taproot forks or stunts. Sow the small seeds 0.6-1.3 cm (1/4-1/2 in) deep, 2.5-5 cm (1-2 in) apart, in rows 35-75 cm (14-30 in) apart, then thin at the first-true-leaf stage to…
Harvesting
Turnip roots are ready roughly 40-60 days from sowing (about 55 days for a medium root), and the key quality cue is root diameter, not the calendar: pull roots at 5-8 cm (2-3 in) across, when they are sweet, crisp and tender. Left beyond ~8-10 cm they turn woody, pithy and pungent, so harvest a touch early rather than…
Planting Calendar
Turnip is a cool-season crop grown for spring and autumn harvests; avoid summer heat, which makes roots woody and bitter and triggers bolting. In temperate zones direct-sow in early spring (about 2-4 weeks before last frost, ~March-April) and again in late summer (~August-September, or 8-10 weeks before first frost)…
Common Issues
Turnip is a fast, hardy cool-season root crop but carries the full pest and disease profile of the mustard family. In a clean, enclosed hydroponic system the everyday problems are physiological and water-borne: root rot (Pythium) in warm, low-oxygen root zones - keep solution below 24C with high dissolved oxygen;…
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