Vegetable
Turnip
Brassica rapa subsp. rapa · Brassicaceae
Turnip (Brassica rapa subsp. rapa) is a moderate-water vegetable well suited to Tucson and the low desert. It thrives in full sun, with a fast growth rate. Expect yellow (flowers only if bolted) blooms Grown for roots/greens.
Turnip at a glance
- Water use
- Moderate (established)
- Sun
- Full sun (6+ hours); tolerates light afternoon shade in the cool season.
- Mature size
- Tops 12-18 in tall; roots 2-4 in diameter.
- Growth rate
- Fast
- Bloom
- Yellow (flowers only if bolted), Grown for roots/greens; harvest roots in ~40-60 days. Bolts (yellow flowers) in spring heat.
- Cold hardiness
- Cool-season; frost-hardy and grows well through Tucson winters. Roots turn woody and pungent and plants bolt as spring warms.
- Soil
- Loose, well-drained, fertile loam amended with compost; remove rocks and break up caliche/clay so roots form cleanly. Near-neutral to slightly alkaline pH is fine.
- Native range
- Europe and western Asia; not native to the Sonoran Desert.
- Best used as
- Cool-season root vegetable, turnip greens as a leaf crop, raised beds and containers, fall through early spring harvest
- Wildlife
- Flowers (if bolted) attract bees and other pollinators.
- Toxicity
- Non-toxic to people and pets; both root and greens are edible.
How to grow Turnip in Tucson & the low desert
Watering
Keep soil consistently moist; in Tucson water deeply about every 2-3 days. Steady moisture keeps roots tender and mild and prevents cracking and woodiness.
Fertilizer & nutrients
Work compost and a balanced fertilizer into the bed before planting. Moderate nitrogen for greens; adequate phosphorus and potassium for root bulking. A light side-dress mid-growth supports both roots and tops.
Pruning & care
No pruning. Thin seedlings to 3-4 in apart; thinnings are edible as greens.
Notes
In Tucson direct-sow in the cool season: fall (roughly Sept-Nov) and again in late winter (Jan-Feb). Harvest roots young (2-3 in) for best flavor and texture; grow some plants for greens, which can be picked while roots are sizing. Avoid hot-season sowing.
Sources: University of Arizona Cooperative Extension (Pima County) low-desert vegetable planting calendar; Pima County Master Gardeners; Arizona Master Gardener Manual