Scarlet Kale (red kale) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun, 6 or more hours daily, for the strongest scarlet colour and sturdiest plants. Cold weather plus bright light intensifies the red; shade keeps leaves greener and looser. If your only bright window faces south, that's perfect for scarlet kale — same window any aroid would fry on.

Watering

Crops like scarlet kale reward consistent watering — when the top 2-3 cm of soil is dry, every 4-7 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. Provide about 2-3 cm of water weekly and keep moisture consistent. Drought stress makes the curled leaves tough and bitter and invites pest attack.

Soil and pot

Scarlet Kale grows best in rich, firm, well-drained loam. Fertile, organic-rich, moisture-retentive soil with a firm root run. Slightly acidic to neutral pH 6.0-7.5; lime toward neutral in brassica beds to limit clubroot. 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

Scarlet Kale sits happiest at around Outdoor ambient humidity and 7-24°C (45-75°F). An outdoor crop with no specific humidity needs; ample spacing keeps the curled foliage dry and discourages aphids and mildew. If you keep the room above 7 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 scarlet kale sparingly. Hungry for nitrogen. Incorporate compost or aged manure before planting and side-dress or liquid-feed with a nitrogen-rich fertiliser every 3-4 weeks to sustain leafy growth and deep colour. 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 scarlet kale in the Growli community. Each is annotated with the most common cause so you know where to start.

• Cabbage caterpillars — Cabbage white and looper caterpillars chew holes and conceal themselves in the curls. Cover with insect mesh, hand-pick, or treat with Bt to protect young plants.
• Cabbage aphid — Grey-waxy aphid colonies pack into the frilled leaves and growing tip. Dislodge with water, use insecticidal soap, and encourage ladybirds and hoverflies.
• Clubroot — Stunting and wilting with swollen, distorted roots in infected soil. Rotate brassicas, raise pH toward neutral with lime, and improve drainage; spores persist for years.
• Faded colour and bitterness — Warm weather keeps leaves greener and tougher. The scarlet hue and sweetness develop with cold; harvest after a frost for the best colour and flavour.

Propagation

Grown from seed. Sow 1 cm deep in modules or a seedbed and transplant at 4-6 weeks, spacing about 45 cm apart and planting firmly; it does not grow from cuttings. 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

Scarlet Kale is mildly toxic to pets. Garden kale (Brassica oleracea) is not individually listed by the ASPCA and is generally non-toxic to dogs, but it contains N-propyl disulfide and thiocyanate/isothiocyanate compounds that can cause Heinz-body hemolytic anemia in cats and GI irritation with repeated or large feeding. Treat as unsafe for cats in quantity and verify with a vet before feeding. 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.

Scarlet Kale deep-dive guides

Every aspect of scarlet kale care, each with its own calibrated guide:

• Scarlet Kale watering schedule
• Scarlet Kale light requirements
• Best soil mix for scarlet kale
• Scarlet Kale fertilizing guide
• When to repot scarlet kale
• How to propagate scarlet kale
• Scarlet Kale growth rate & size
• Scarlet Kale cold hardiness
• Scarlet Kale temperature & humidity
• Is scarlet kale toxic to cats & dogs?
• Is scarlet kale toxic to cats?
• Is scarlet kale toxic to dogs?

Related guides

Scarlet Kale is also commonly called Scarlet kale or red kale.

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