Kohlrabi 'Superschmelz' (Superschmelz kohlrabi) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun, 6+ hours, for full, even bulb size; shaded plants produce smaller bulbs and more leaf than stem. If your only bright window faces south, that's perfect for kohlrabi 'superschmelz' — same window any aroid would fry on.

Watering

Crops like kohlrabi 'superschmelz' reward consistent watering — keep evenly moist; water when the top 2-3 cm is dry, about every 3-4 days. The mistake is the daily light sprinkle: it never reaches the deeper roots. A long soak twice a week beats a five-minute splash every day. Consistent watering is essential for the smooth, tender, non-woody flesh this variety is known for; fluctuating moisture causes splitting. Mulch to steady soil moisture.

Soil and pot

Kohlrabi 'Superschmelz' grows best in deep, fertile, firm, well-drained loam. Rich, organic soil, pH 6.0-7.5, firmed to anchor the large bulbs. Lime acidic soils toward neutral to deter clubroot. Needs room; better in beds than small containers. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Kohlrabi 'Superschmelz' sits happiest at around 40-70% humidity and 10-24°C (50-75°F). Outdoor crop indifferent to air humidity; steady soil moisture is what governs bulb quality. Space well to reduce fungal leaf disease. If you keep the room above 10 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed kohlrabi 'superschmelz' sparingly. Moderate-to-heavy feeder for its size: enrich soil with compost or balanced fertiliser, then feed every 3-4 weeks; favour balanced feeding over high nitrogen to build sweet, firm bulbs rather than excess leaf. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on kohlrabi 'superschmelz' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Splitting at large size — Even this tender giant can crack if watering swings between dry and wet. Keep moisture even and harvest before bulbs over-mature.
• Clubroot — Distorted, swollen roots and poor bulbing in infected brassica soil. Rotate crops, lime to near-neutral pH, and ensure good drainage.
• Cabbage white caterpillars — Larvae shred the leafy crown in summer, weakening growth. Net with insect mesh and remove eggs and caterpillars.
• Cabbage root fly — Larvae attack roots, causing wilting and stunted bulbs. Use stem-base collars or fleece transplants to deter egg-laying.

Propagation

From seed. Sow in modules or direct 1 cm deep and thin/transplant to 30-45 cm apart to accommodate the giant bulbs. Sow in late spring to early summer for autumn and winter harvest. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Kohlrabi 'Superschmelz' is mildly toxic to pets. Brassica oleracea kohlrabi is usually tolerated by cats and dogs in small cooked amounts, but the ASPCA's Brassica/Indian Mustard listing is toxic to horses (isothiocyanates; gastrointestinal irritation and colic), and the genus's isothiocyanates can cause GI upset, gas, and bloating in pets, with thiocyanate risk from large repeated quantities. Keep away from horses and consult a vet for any unwell animal. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Kohlrabi 'Superschmelz' deep-dive guides

Every aspect of kohlrabi 'superschmelz' care, each with its own calibrated guide:

• Kohlrabi 'Superschmelz' watering schedule
• Kohlrabi 'Superschmelz' light requirements
• Best soil mix for kohlrabi 'superschmelz'
• Kohlrabi 'Superschmelz' fertilizing guide
• When to repot kohlrabi 'superschmelz'
• How to propagate kohlrabi 'superschmelz'
• Kohlrabi 'Superschmelz' growth rate & size
• Kohlrabi 'Superschmelz' cold hardiness
• Kohlrabi 'Superschmelz' temperature & humidity
• Is kohlrabi 'superschmelz' toxic to cats & dogs?
• Is kohlrabi 'superschmelz' toxic to cats?
• Is kohlrabi 'superschmelz' toxic to dogs?

Related guides

Kohlrabi 'Superschmelz' is also commonly called Superschmelz kohlrabi or giant white kohlrabi.

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