How to Grow Kohlrabi
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Kohlrabi
Brassica oleracea var. gongylodes
vegetableKohlrabi is a cool-season cruciferous vegetable that produces a swollen, bulbous stem above ground with leaves extending from it. Often called a "space cabbage," it has a mild, slightly sweet flavor similar to cabbage stem or turnip and is highly nutritious. The edible bulb can be harvested when small and tender or left to grow larger depending on variety.
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Example Kohlrabi timeline · Pittsburgh, PA (Zone 6b)
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Plant Kohlrabi
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Kohlrabi
Around Jun 1≈ 45 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Kohlrabi dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9; grows best in cool seasons, can be grown spring or fall in most regions
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Get my Kohlrabi timeline →Growth Stages
Seedling
2-3 weeksTiny cotyledons emerge, followed by true leaves that look similar to cabbage. Plants are delicate and vulnerable to pests.
Keep soil consistently moist. Provide bright light if indoors. Thin seedlings to prevent crowding when first true leaves appear. Start indoors 4-6 weeks before transplant date.
Early Vegetative
2-3 weeksLeaves develop steadily, forming a small rosette. The stem base begins to thicken slightly but is not yet noticeably bulbous.
Transplant when 3-4 true leaves present. Harden off seedlings before planting outdoors. Water consistently and apply light mulch. Begin pest monitoring.
Bulb Development
2-3 weeksThe stem swells rapidly to form the characteristic bulbous shape. Leaves continue expanding around the bulb. This is the most critical growth period.
Maintain consistent moisture to prevent splitting and woodiness. Keep bulb mostly above soil surface for even development. Side-dress with compost or balanced fertilizer mid-stage. Monitor for cabbage worms and flea beetles intensively.
Harvest-Ready
5-7 days (harvest window)Bulbs reach desired size (2-3 inches diameter for tender texture, up to 6 inches for larger varieties). Surface may feel slightly woody if left too long.
Begin harvesting at 2 inches for best tenderness, or wait for 4-6 inches depending on preference. Harvest from bottom by cutting the bulb with a knife, leaving leaves attached. Do not wait too long past peak maturity or quality declines.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Handpick larvae; use floating row covers; apply Bacillus thuringiensis (Bt); plant trap crops like nasturtiums
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Use row covers on young plants; spray neem oil or kaolin clay; dust with food-grade diatomaceous earth; remove weeds nearby
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Strong water spray to dislodge; insecticidal soap; neem oil; encourage natural predators like ladybugs
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Improve drainage and soil pH to 6.8+; rotate crops; remove infected plants; do not replant brassicas in same spot for 3-4 years
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Yellow sticky traps; neem oil; insecticidal soap; vacuum pests with hand-held device
Uses
Fresh eating and cooking
CulinaryRaw kohlrabi bulbs are crunchy and mildly sweet, excellent sliced in salads, stir-fries, or roasted. The leaves are also edible and nutritious, with a flavor similar to kale. [source]
Nutritional powerhouse
CulinaryHigh in vitamin C, fiber, potassium, and manganese. Low in calories and carbohydrates, making it suitable for various diets. [source]
Antioxidant and anti-inflammatory properties
MedicinalContains glucosinolates and other phytonutrients associated with reduced inflammation and potential cancer-protective effects, common to brassicas. [source]
Long storage potential
HouseholdKohlrabi keeps well in cool, humid storage (refrigerator or root cellar) for 3-4 weeks, making it excellent for food preservation and extended pantry use. [source]
Pollinator and predator plant
WildlifeFlowering kohlrabi left to bolt provides nectar and pollen for bees and beneficial insects, supporting garden ecosystem health. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest when bulbs are 2-3 inches in diameter for maximum tenderness and mild flavor, or up to 4-6 inches for larger varieties. Use a sharp knife to cut the bulb just below the swollen portion, leaving 1-2 inches of stem. Harvest in morning when plants are cool. Leave the plant in ground and continue harvesting leaves, or pull entire plant. Young bulbs can be left in soil 2-3 weeks at peak maturity in cool weather; they deteriorate faster in heat. For fall crops, time planting so harvest occurs before first frost (kohlrabi tolerates light frost but quality declines in freezing temperatures).
Fun Facts
- 🌱 Kohlrabi's name comes from German: 'Kohl' (cabbage) + 'Rabi' (turnip), reflecting its hybrid appearance. It was developed in northern Europe in the 15th century.
- 🌱 The bulb grows above ground making it easy to harvest and monitor, unlike root crops. In ideal growing conditions, kohlrabi can double in size within 1-2 weeks.
- 🌱 Both the bulb and leaves are completely edible and nutritious—nothing goes to waste. Smaller kohlrabi bulbs (2-3 inches) are tender and mild, while larger specimens can develop a woody, cabbage-like texture if overmatured.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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