How to Grow Purple Vienna Kohlrabi
Brassica oleracea var. gongylodes 'Purple Vienna'
Purple Vienna Kohlrabi is a vibrant, heirloom brassica prized for its crisp, sweet bulb that tastes like a cross between cabbage and apple. Gardeners grow this easy-to-cultivate cool-season crop to add colorful texture and nutritious crunch to salads or roasted vegetable medleys before it bolts in the heat.
Starting Purple Vienna Kohlrabi: indoors or direct sow?
🌾 Sow directly in the garden — Purple Vienna Kohlrabi is not usually started indoors.
You should sow seeds directly into the garden rather than starting indoors, planting them two to six weeks before the last frost date.
Soil, care & harvest
Prepare loose, fertile soil with a pH between 6.0 and 7.5 for best results. As a cool-season brassica, you should sow seeds directly outdoors two to six weeks before your last expected spring frost date. Press seeds lightly into the soil at a depth of about one-quarter inch. Expect germination within seven to ten days once temperatures are suitable.
Space plants six to eight inches apart to allow bulbs to swell properly without crowding. While they do not require trellising, keep the soil consistently moist with about an inch of water weekly to prevent bitterness. Apply a light layer of mulch around the base to retain moisture and suppress weeds, feeding lightly if growth seems sluggish.
Watch for flea beetles, cabbage worms, and aphids; use row covers or insecticidal soap early to deter them. Clubroot and black rot can be prevented by rotating crops and ensuring good drainage. Harvest the bulb when it reaches a convenient size, typically sixty to seventy days after sowing, while the plant is still green.
When to Plant Purple Vienna Kohlrabi
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | April – May | June – July | August – September |
| Zone 2 | April – May | May – July | July – September |
| Zone 3 | March – April | May – June | July – October |
| Zone 4 | March – April | April – June | June – October |
| Zone 5 | February – March | April – May | June – November |
| Zone 6 | February – March | April – May | June – November |
| Zone 7 | February – March | March – May | May – November |
| Zone 8 | January – February | March – April | May – December |
| Zone 9 | January | February – March | April – December |
| Zone 10 | January | January – March | March – December |
| Zone 11 | January | January – February | February – December |
| Zone 12 | January | January – February | February – December |
| Zone 13 | January | January – February | February – December |
Companion Plants for Purple Vienna Kohlrabi
✓ Good companions
Repels cabbage white butterflies and other brassica pests
Attracts beneficial wasps that parasitize cabbage worms and aphids
Deters cabbage loopers and aphids while improving soil health
Acts as living mulch, conserving soil moisture and maximizing garden space
Repel nematodes and general garden pests while attracting beneficial insects
Trap crop for aphids and flea beetles, draws pests away from kohlrabi
Repel cabbage worms, aphids, and flea beetles that commonly attack brassicas
Complements root depth and nutrient uptake without competing directly
✗ Keep away from
Can shade kohlrabi and compete for nitrogen in soil
May inhibit brassica growth and attract slugs that damage young kohlrabi
Compete for similar nutrients and may stunt kohlrabi growth
Nutrition Facts
Per 100g serving (USDA FoodData Central)
