GardenKohlrabi variety
Grand Duke Kohlrabi
✓ In your garden
Grand Duke is a green kohlrabi, ready in about 45–50 days. You eat the crisp, swollen stem — mild and sweet like a cabbage-turnip, good raw or cooked. It’s quick and cool-season; harvest while it’s tennis-ball-sized, before it turns woody.
“A crisp, mild swollen stem — half cabbage, half turnip.”
Growing basics — shared by every kohlrabi
Grand Duke grows like any other kohlrabi. The full picture — how deep to plant, spacing, feeding, pests, harvest — lives on the Kohlrabi page so it's maintained in one place.
- Sun
- Full Sun
- Spacing (in row)
- 4–6 in
- Row spacing
- 12–24 in
- Planting depth
- 0.25–0.5 in
- Soil pH
- 6–7.5
- Water
- Moderate
What is Grand Duke good for?
- Raw & slawsPeel and eat it like an apple. Great
- Roasted / sautéedMild and sweet cooked. Great
- Big / old bulbsTurns woody — pick young. Skip it
From how it grows — kitchens vary.
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Want the full 10/50/90% odds + nearest stations? Open the frost tool →When to plant Grand Duke in your zone
Zone 6bGreenhouse or cover on: your start slides ~4 weeks earlier and your harvest stretches ~3 weeks later (shown striped).
Planting seeds straight in the ground only works where the season's long and warm — most gardeners start seeds indoors or buy young plants, or you'd pick your first tomato right as frost hits.
Comfortable — first ripe fruit lands around mid May, well before your typical frost (~late Oct).
- Start seeds indoors
- mid Feb – early Mar
- Toughen up outside
- late Mar – early Apr
- Move plants outside
- early Apr – early Apr
- Plant seeds outside
- early Apr – early Apr
- Growing
- early Apr – mid May
- Picking
- mid May – early Jun
Typical dates for zone 6b — set your zone or ZIP above for yours.
Growing Grand Duke — the things that trip people up
- Pick it young — tennis-ball-sized. Left too long it turns woody and hot. It grows fast, so it’s a great catch crop in spring and fall.
- Brassicas are cool-season — they bolt or turn bitter in summer heat, so grow them in spring and fall. Feed them well and watch for cabbage worms (the little green caterpillars); a floating row cover keeps the moths off.
Grand Duke kohlrabi at a glance
| Type | Green |
|---|---|
| Days to ripe | 45–50 days after you plant it outside |
| Color | Green |
Extra fields from seed-catalog listings and university growing guides. Days to ripe and disease resistance shift with your climate and seed source — double-check with your local extension office before you buy.
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Common questions about Grand Duke
How long does Grand Duke take to grow?
About 45–50 days from transplant. Start seeds indoors and set out young plants for a strong start.
When should I grow Grand Duke?
In the cool of spring or fall — brassicas bolt and turn bitter in summer heat. Fall crops often taste best, sweetened by a light frost.
Browse more kohlrabi varieties →