Giant Kohlrabi
A supersized kohlrabi variety that can grow to the size of a basketball without becoming woody or fibrous.
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Meet Giant Kohlrabi
A supersized kohlrabi variety that can grow to the size of a basketball without becoming woody or fibrous. Unlike standard kohlrabi, giant varieties maintain their tender, crisp texture even at large sizes. Provide rich, consistently moist soil and steady fertilization for even growth without cracking. Excellent for slaws, stir-fries, and soups where the mild, sweet flavor adds substance.
When to plant Giant Kohlrabi
Direct sow seeds one-quarter inch deep once soil temperatures reach 45 degrees Fahrenheit. Thin seedlings to 12 to 18 inches apart when they have 2 true leaves. For transplanting, start indoors 4 to 6 weeks before the last frost. Germination takes 5 to 10 days at 60 to 70 degrees. Giant varieties need more space and time than standard kohlrabi, so plan accordingly.
Your Giant Kohlrabi Year
Composed for Zone 7 · typical seasons · frost passes Apr 2, returns Nov 1
Sow Giant Kohlrabi Mar – Apr, Aug – Sep, pick Jun – Jul, Oct – Nov. Set your climate below and every date on this plate re-times itself.
How to grow Giant Kohlrabi
Giant kohlrabi varieties can produce swollen stems weighing 5 to 10 pounds or more while remaining tender and sweet, unlike standard kohlrabi that becomes woody at large sizes. Direct sow seeds one-quarter inch deep in spring or late summer, spacing 12 to 18 inches apart in rows 24 inches apart. Seeds germinate in 5 to 10 days at 60 to 70 degrees Fahrenheit.
Giant kohlrabi needs a longer growing season of 80 to 130 days compared to standard varieties. Keep soil consistently moist and fertile for steady, continuous growth, which is essential for maintaining tender texture at large sizes. Mulch around plants to retain moisture and keep roots cool.
Side-dress with balanced fertilizer every 3 to 4 weeks. Giant kohlrabi tolerates both heat and cold better than standard types, making it versatile across seasons. Harvest when the swollen stem reaches 6 to 10 inches in diameter. Unlike regular kohlrabi, properly grown giant varieties remain remarkably tender and crisp even at large sizes.
10 plants fit a 4 × 8 ft bed
Each Giant Kohlrabi wants 45 cm of elbow room. The planner keeps that spacing for you — every plant, every bed.
Giant Kohlrabi's best neighbours
Plant giant kohlrabi alongside onions, beets, and aromatic herbs like dill and thyme to deter cabbage pests. Lettuce and spinach make good ground-cover companions that shade the soil. Avoid planting near tomatoes, peppers, and strawberries. Nasturtiums planted nearby attract aphids away from the kohlrabi.
Beet belongs beside it. Tomato doesn't.
Old growers' knowledge, checked against Giant Kohlrabi's real companion table below — test any plant you're growing.
Related growing guides
Feed it well
Giant kohlrabi needs fertile, well-drained soil with a pH between 6.0 and 7.5. Work in generous amounts of compost and balanced granular fertilizer before planting. Side-dress every 3 to 4 weeks with a balanced fertilizer to maintain steady growth, which is key to keeping the flesh tender at large sizes. Consistent moisture is critical; irregular watering leads to woody, cracked stems.
Ideal Temperature
Hardiness Zone Compatibility
From seed to harvest, stage by stage
Seed Starting
Seeds germinate readily in cool to moderate soil temperatures between 10-25°C (50-77°F). The small round seeds produce sturdy seedlings with broad, rounded cotyledon leaves typical of the brassica family. Giant varieties can be direct-sown or started indoors 4-6 weeks before the intended transplant date.
Seedling Development
True leaves develop with the characteristic blue-green color and slightly lobed edges of brassicas. The seedling establishes a strong root system and begins building the leaf canopy that will fuel bulb development. At this stage, giant varieties are indistinguishable from standard kohlrabi.
Leaf Canopy Expansion
The plant develops a substantial rosette of large, paddle-shaped leaves that can span 50-60 cm across. These broad leaves act as solar panels, capturing energy that will be stored in the developing bulb. The stem base begins to thicken noticeably above the soil line.
Bulb Formation
The swollen stem bulb expands rapidly above the soil surface, growing from tennis-ball size to its impressive final dimensions. The bulb's skin transitions from pale green or purple to a smooth, waxy finish. Giant varieties put on most of their size during this 6-week period and can gain 100-200 grams per week under ideal conditions.
Bulb Maturation
The bulb reaches its full size of 15-25 cm in diameter, weighing 2-5 kg depending on variety and growing conditions. Unlike standard kohlrabi, giant varieties maintain their tender, crisp texture even at very large sizes. The outer skin becomes firm and waxy while the interior stays juicy and sweet.
Harvest and Storage
Cut the bulb from the root at soil level and trim the leaves, leaving 2-3 cm of stem. Giant kohlrabi stores exceptionally well — whole bulbs keep for 2-3 months in a cool root cellar or refrigerator crisper drawer. The dense flesh actually improves slightly in sweetness after a few weeks of cold storage.
Sow seeds 1 cm deep in moist, well-draining soil. Keep soil consistently moist but not waterlogged. Indoor starts benefit from cool conditions around 15-18°C (60-65°F) to produce stocky, compact seedlings rather than leggy ones.
Caring for Giant Kohlrabi month by month
What to do each month for your Giant Kohlrabi
July
You are hereSpring-planted giant kohlrabi enters peak bulb expansion. Continue regular watering and feeding. In zones 5-7, transplant fall-crop seedlings into beds vacated by spring harvests. Monitor for cabbage aphids and treat with insecticidal soap if needed.
Know exactly what to do in your garden — every month
One email at the start of each month: what to sow, plant, and tackle right now — for your Giant Kohlrabi and everything growing around it. Plus a short starter course that helps you dodge the classic mistakes.
- What to do, right now
- Matched to your season
- Starter course included
Harvesting Giant Kohlrabi
Harvest giant kohlrabi when the swollen stem reaches 6 to 10 inches in diameter, though properly grown specimens can reach even larger sizes while staying tender. Cut the stem at soil level with a sharp knife. Test tenderness by pressing a fingernail into the skin; it should pierce easily. Remove leaves and the tough base before storage. Giant varieties hold well in the ground and can be harvested over several weeks.
assuming you sow when the window opens — set your real date
Pick Giant Kohlrabi promptly and the plant keeps producing.
Storage & Preservation
Giant kohlrabi stores exceptionally well, lasting 2 to 3 months in a cool root cellar or 4 to 6 weeks refrigerated. Peel the tough outer skin before eating. For freezing, peel, dice, blanch for 2 minutes, and freeze in bags. Kohlrabi can be fermented like sauerkraut or pickled in vinegar. Thin slices also dehydrate well for snacking.
What goes wrong — and the fix
Cabbage Root Maggots
PestWilting plants, tunnels in the swollen stem, and small white maggots visible when stem is cut open.
Flea Beetles
PestSmall round holes peppering the leaves, especially damaging to young seedlings.
Clubroot
DiseaseWilting in warm weather, yellowing leaves, stunted growth, and swollen distorted roots.
Troubleshooting Common Problems
The main challenge with giant kohlrabi is achieving consistent, uninterrupted growth to prevent woodiness. Any stress from drought, nutrient deficiency, or temperature extremes can cause the flesh to become tough and fibrous. Splitting occurs from sudden heavy watering after dry periods. Cabbage root maggots can tunnel into the enlarged stem, ruining the crop.
Growing Tips
- Choose a true giant variety — this is critical. Standard kohlrabi varieties turn woody and bitter past 8-10 cm in diameter. Only varieties bred for giant production like Superschmelz, Kossak, or Gigante maintain their tender texture at large sizes. Do not expect standard varieties to behave like giants simply by growing them longer.
- Time your planting so bulb formation coincides with cool weather. Giant kohlrabi needs 130-150 days to reach full size, so count backward from your first fall frost for a fall harvest, or plant early in spring for a midsummer harvest in cooler climates. Heat during bulb formation ruins quality.
- Consistent moisture is the single most important factor for quality bulbs. Irregular watering causes the bulb to crack, develop hollow centers, or turn woody. Water deeply 2-3 times per week rather than lightly every day, and mulch heavily to maintain even soil moisture.
- Space plants generously at 40-50 cm apart in rows 60 cm apart. Giant kohlrabi needs room for both its extensive leaf canopy and its bulb, which can reach 25 cm in diameter. Crowded plants produce undersized, misshapen bulbs.
- Feed steadily but avoid excess nitrogen. A balanced fertilizer (10-10-10) every 2-3 weeks supports steady growth. Too much nitrogen produces enormous leaves but smaller, softer bulbs. Switch to a lower-nitrogen formula once bulb swelling begins.
- Do not panic if the bulb seems slow to form. Giant varieties invest heavily in leaf canopy before bulb development begins in earnest around day 60-70. The large leaf surface is necessary to fuel the rapid bulb expansion that follows.
- Harvest at your convenience — giant kohlrabi is extremely forgiving. Unlike standard varieties that deteriorate quickly if left in the ground too long, giant kohlrabi can remain in the garden for 2-3 weeks past peak maturity without losing quality, especially in cool autumn weather.
- Save the leaves for cooking. Giant kohlrabi produces large, tender leaves that are delicious sauteed with garlic and olive oil, added to soups, or used as wraps. The leaves are actually more nutritious than the bulb, containing higher concentrations of vitamins A, C, and iron.
Pick your Giant Kohlrabi
Superschmelz
The premier giant variety, producing tender, sweet bulbs up to 10 pounds that never become woody.
Kossak
A hybrid giant kohlrabi reaching 8 to 10 inches across with excellent texture and mild sweet flavor.
Gigante
An Italian heirloom producing very large pale green bulbs with crisp, sweet flesh.
Giant kohlrabi is rarely available in grocery stores, and when found at farmers markets or specialty shops, it typically sells for $4-8 per kilogram. A single plant grown from a $3-4 seed packet (containing 50-100 seeds) can produce a 3-5 kg bulb worth $12-40 at market prices. Growing 4-6 plants provides 10-25 kg of produce worth $40-200, all from a single seed packet. The exceptional storage life (2-3 months in cold storage) means the savings extend well into winter when fresh local produce is most expensive.
Quick recipes
Creamy Kohlrabi and Apple Slaw
15 minA refreshing raw slaw that highlights giant kohlrabi's apple-crisp texture and mild sweetness. Shredded kohlrabi pairs perfectly with tart green apple and a tangy yogurt dressing for a light, crunchy side dish that works with grilled meats or as a standalone salad.
8 ingredients
Roasted Kohlrabi Wedges with Herbs
40 minHigh-heat roasting transforms giant kohlrabi into tender, caramelized wedges with golden edges and a nutty, sweet depth of flavor that surprises first-time tasters. A simple preparation that converts even kohlrabi skeptics.
7 ingredientsKohlrabi Schnitzel (German-Style Cutlets)
30 minA traditional German recipe where thick kohlrabi slices are breaded and pan-fried into crispy golden cutlets — a beloved vegetarian main course. Giant kohlrabi's dense, meaty texture makes it the perfect stand-in for traditional schnitzel.
7 ingredientsCulinary Uses
Giant kohlrabi has a sweet, mild flavor similar to broccoli stems or turnip. Peel and eat raw in sticks with dip, shred into coleslaw, or grate into salads. Roast cubes until caramelized, add to stir-fries, or simmer in soups and stews. It makes an excellent low-carb substitute for potatoes in gratins and mashes.
What's inside
Health Benefits
- Exceptionally rich in vitamin C, providing 69% of the daily value per 100g — a powerful antioxidant that supports immune defense, collagen synthesis, iron absorption, and protection against oxidative cellular damage.
- Contains glucosinolates and isothiocyanates, sulfur-containing compounds extensively researched for their potential to inhibit cancer cell growth, particularly in colorectal, breast, and prostate cancers.
- High in dietary fiber (3.6g per 100g) that supports digestive regularity, feeds beneficial gut microbiota, and may help reduce LDL cholesterol levels by binding bile acids in the intestine.
- Good source of potassium (350mg per 100g) which helps regulate blood pressure by counteracting the effects of dietary sodium, supports proper muscle contraction, and maintains healthy fluid balance.
- Provides B vitamins including B6 and folate, essential for homocysteine metabolism, neurotransmitter synthesis, and red blood cell formation — supporting cardiovascular and neurological health.
- Very low calorie density (27 kcal per 100g) combined with high water and fiber content creates strong satiety, making giant kohlrabi an excellent food for weight management and metabolic health.
Where Giant Kohlrabi comes from
Kohlrabi (Brassica oleracea var. gongylodes) is believed to have been developed through selective breeding in northern Europe during the late medieval period, with the earliest written descriptions appearing in the 1550s by the Italian botanist Pietro Andrea Mattioli. Unlike its ancient brassica relatives — cabbage, kale, and broccoli — kohlrabi is a comparatively modern vegetable, selected for its unique swollen stem rather than its leaves, flowers, or buds.
The vegetable gained particular popularity in German-speaking regions of Europe, where it became a staple in peasant and farmhouse cookery. By the 17th and 18th centuries, kohlrabi was widely grown across Germany, Austria, Switzerland, and Eastern Europe. It was valued for its hardiness, rapid growth, and versatility in the kitchen — eaten raw, cooked, or stored through the winter months. The giant varieties that exist today trace their lineage to Austrian and Bavarian breeding programs that selected for bulbs that could grow to extraordinary sizes without developing the woodiness that plagues standard varieties past a certain diameter.
Superschmelz, the most famous giant kohlrabi, was developed in the mid-20th century and remains the benchmark for oversized kohlrabi breeding. It can produce bulbs weighing 4-10 kg while maintaining the crisp, sweet, juicy texture of a much smaller bulb — a remarkable achievement in vegetable breeding. Today, giant kohlrabi is enjoying a renaissance among home gardeners and specialty market farmers in Europe and North America, prized for its impressive yields, long storage life, and the sheer novelty of harvesting a single vegetable the size of a bowling ball.
Giant Kohlrabi: did you know?
Fascinating facts about Giant Kohlrabi
Giant kohlrabi varieties like Superschmelz were developed in Austrian and German agricultural regions specifically to grow to enormous sizes (up to 10 kg) while remaining tender and sweet — a feat no standard kohlrabi can match, as regular varieties turn woody past tennis-ball size.
Giant Kohlrabi questions, answered
When should I plant Giant Kohlrabi?
What are good companion plants for Giant Kohlrabi?
What hardiness zones can Giant Kohlrabi grow in?
How much sun does Giant Kohlrabi need?
How far apart should I space Giant Kohlrabi?
What pests and diseases affect Giant Kohlrabi?
How do I store Giant Kohlrabi after harvest?
What are the best Giant Kohlrabi varieties to grow?
What soil does Giant Kohlrabi need?
What is the difference between giant kohlrabi and regular kohlrabi?
How do I know when giant kohlrabi is ready to harvest?
Can I grow giant kohlrabi in hot climates?
How should I store giant kohlrabi after harvest?
What does giant kohlrabi taste like and how is it eaten?
Is giant kohlrabi frost-tolerant?
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