Vegetable
Kohlrabi
Brassica oleracea var. gongylodes · Brassicaceae
Also called: German turnip, Turnip cabbage
Kohlrabi (Brassica oleracea var. gongylodes) is a moderate-water vegetable well suited to Tucson and the low desert. It thrives in full sun.
Kohlrabi at a glance
- Water use
- Moderate (established)
- Sun
- Full sun (6+ hours); light afternoon shade is fine in late-season warmth.
- Mature size
- Swollen edible stem 2-4 in across; plant about 12 in tall and wide.
- Growth rate
- Fast (about 45-60 days from transplant to harvest).
- Bloom
- Yellow (only if allowed to bolt; not desirable for eating), Harvest fall-winter and spring in Tucson; harvested vegetatively before flowering.
- Cold hardiness
- Cool-season crop, frost-hardy to about 25-28 F; grown through Tucson's mild winters. USDA 9a-9b.
- Soil
- Fertile, well-drained loam high in organic matter; amend caliche/clay soils with compost. pH 6.0-7.5; tolerates alkaline desert soil.
- Native range
- Cultivated form of wild cabbage native to coastal Western/Southern Europe and the Mediterranean
- Best used as
- Edible vegetable (raw or cooked; mild sweet-cabbage/broccoli-stem flavor), Quick cool-season raised-bed crop
- Wildlife
- Susceptible to cabbage loopers, aphids, and harlequin bugs; floating row cover helps in the low desert.
- Toxicity
- Non-toxic and edible for humans and pets.
How to grow Kohlrabi in Tucson & the low desert
Watering
Cool-season planting: sow seed or set transplants Sep-Nov and again Jan-Feb. Keep soil evenly moist; water deeply 2x/week. Consistent moisture is critical, dry spells make the bulb woody and split.
Fertilizer & nutrients
Moderate to heavy feeder. Work compost and a balanced fertilizer into the bed at planting and side-dress with nitrogen once mid-cycle to keep stems tender and fast-growing.
Pruning & care
No pruning needed. Harvest the swollen stem promptly when 2-3 in across; oversized bulbs turn woody.
Notes
One of the faster brassicas, ideal for succession plantings in Tucson's cool season. Harvest young for the best crisp, mild texture. Not native; no landscape use.
Sources: University of Arizona Cooperative Extension - Pima County Vegetable Planting and Harvesting Guide (extension.arizona.edu); University of Arizona Cooperative Extension - Pima County Monthly Gardening Guides (extension.arizona.edu)