Mizuna 'Red Kingdom' (Red mizuna) care

Light

Most houseplants will scorch where mizuna 'red kingdom' thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Full sun deepens the red-purple pigment and keeps growth compact; in shade the colour fades toward green. Light afternoon shade helps only in extreme summer heat. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

For mizuna 'red kingdom' in the ground or in a bed, aim for even moisture, around 2.5 cm (1 inch) per week. Soak the root zone rather than misting the foliage; deep, less-frequent watering trains roots downward and produces a more drought-resilient plant by mid-season. Consistent watering keeps leaves tender and mild and discourages bolting; let the soil dry and the foliage turns tough and sharply pungent. Water more in heat and pots.

Soil and pot

Mizuna 'Red Kingdom' grows best in fertile, well-drained loam. Organic-rich and moisture-retentive with a pH near 6.0-7.0. Compost-improved ground supports fast, repeated cut-and-come-again regrowth. 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

Mizuna 'Red Kingdom' sits happiest at around Ambient outdoor humidity and 10-24°C (50-75°F). No special humidity requirement; airy spacing on the dense rosettes limits mildew and rot during damp weather. 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 mizuna 'red kingdom' sparingly. Light feeder for fast leaves. Compost-enriched soil plus a dilute balanced or nitrogen-leaning liquid feed every couple of weeks sustains vigorous, well-coloured regrowth. 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 mizuna 'red kingdom' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Fading colour — Low light and warmth dull the red-purple to green. Grow in full sun during cool weather to hold the strongest pigment.
• Flea beetles — Pepper the serrated leaves with shotholes, worst on seedlings. Use fine insect mesh from sowing and keep plants moist and growing strongly.
• Bolting — Heat and long days send plants to flower and toughen the leaves. Sow in cooler windows, cut young, and maintain even moisture.
• Slugs and snails — Shelter in the dense rosette and graze new growth in wet weather. Use barriers or traps and harvest in dry spells for clean leaves.

Propagation

Sow seed 1 cm deep, broadcast for baby leaf or in rows for full plants; germinates in 4-8 days. Resow every 2-3 weeks and cut regularly to encourage fresh, well-coloured regrowth. 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

Mizuna 'Red Kingdom' is mildly toxic to pets. Brassica rapa mustard greens are not individually listed on the ASPCA toxic plant database, so a pet-safe label cannot be asserted; treat with caution and verify with a vet. Brassicas contain isothiocyanates and goitrogens, and large quantities can cause gas, GI upset, or thyroid effects in pets, so feed only in small amounts. 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.

Mizuna 'Red Kingdom' deep-dive guides

Every aspect of mizuna 'red kingdom' care, each with its own calibrated guide:

• Mizuna 'Red Kingdom' watering schedule
• Mizuna 'Red Kingdom' light requirements
• Best soil mix for mizuna 'red kingdom'
• Mizuna 'Red Kingdom' fertilizing guide
• When to repot mizuna 'red kingdom'
• How to propagate mizuna 'red kingdom'
• Mizuna 'Red Kingdom' growth rate & size
• Mizuna 'Red Kingdom' cold hardiness
• Mizuna 'Red Kingdom' temperature & humidity
• Is mizuna 'red kingdom' toxic to cats & dogs?
• Is mizuna 'red kingdom' toxic to cats?
• Is mizuna 'red kingdom' toxic to dogs?

Related guides

Mizuna 'Red Kingdom' is also commonly called Red mizuna or purple mizuna.

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