Fertilising guide
How to fertilise Mizuna 'Red Kingdom' (Brassica rapa var. nipposinica 'Red Kingdom')— schedule & NPK
Also called Red mizuna, purple mizuna.
More about mizuna 'red kingdom'
About Mizuna 'Red Kingdom'
Brassica rapa var. nipposinica 'Red Kingdom' · also called Red mizuna, purple mizuna · edible
'Red Kingdom' is an F1 red mizuna with deeply serrated purple-red leaves on slim stems, adding colour and a mild mustard bite to salad mixes. Vigorous and slow to bolt, it holds its rich pigment best in cool weather and bright light, regrows well after cutting, and tolerates light frost, making it a standout baby-leaf and stir-fry green.
Growth habit: Upright rosette of finely cut purple-red leaves on thin stems; a biennial grown as an annual that bolts to a flowering stalk under heat or long days.
What fertiliser mizuna 'red kingdom' actually wants — and why
Mizuna 'Red Kingdom' is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.
A nitrogen-leaning feed (higher first number) or compost-rich soil — nitrogen drives the fast, tender leafy growth this crop is grown for. Phosphorus and potassium matter far less here than for fruiting crops.
For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for mizuna 'red kingdom': match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.
How often to feed mizuna 'red kingdom', and which months
Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For mizuna 'red kingdom':
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. In practice: a balanced or compost-rich start, then a nitrogen side-dress or liquid feed every 3-4 weeks through the cropping period in the main season (spring through early autumn).
The dormant-season rule matters more than the exact interval: skip feeding entirely when mizuna 'red kingdom' is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.
What strength to mix for mizuna 'red kingdom'
Use the vegetable-feed label rate for mizuna 'red kingdom'. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
Feeding always goes onto already-damp soil, never dry roots — water mizuna 'red kingdom' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the mizuna 'red kingdom' watering schedule.
Signs you are over-feeding mizuna 'red kingdom'
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for mizuna 'red kingdom':
- Very soft, floppy, dark-green growth that attracts aphids.
- Excess leafy growth at the expense of hearts/heads in cabbage and the like.
- Salt crust and scorched leaf edges in containers; nitrate-heavy leaves.
Signs you are under-feeding mizuna 'red kingdom'
- Pale, yellow-green leaves, oldest first, and slow growth.
- Small, tough, bitter leaves and premature bolting.
- Weak, stunted heads in cabbage, broccoli and cauliflower.
If the symptoms point at watering, light or roots rather than nutrition, the full mizuna 'red kingdom' care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
For container-grown mizuna 'red kingdom', water until it drains freely each time and flush pots monthly with plain water to stop nitrogen salts accumulating; in the ground, good compost levels naturally buffer this.
Organic vs synthetic feeds for mizuna 'red kingdom'
Organic options
Well-rotted manure or compost dug in, plus nitrogen-rich liquid feeds like diluted chicken-manure pellets or nettle feed. UK: pelleted chicken manure or Westland; US: Espoma Garden-tone or blood meal. Steady and soil-building.
Synthetic / liquid feeds
A balanced feed at planting then a high-nitrogen liquid or granular side-dress — UK: Growmore then a nitrogen feed or Phostrogen; US: a 10-10-10 then a high-N (e.g. 21-0-0) side-dress or Miracle-Gro.
Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.
Fertilising mizuna 'red kingdom' — frequently asked questions
What fertiliser does mizuna 'red kingdom' need?
A nitrogen-leaning feed (higher first number) or compost-rich soil — nitrogen drives the fast, tender leafy growth this crop is grown for. Phosphorus and potassium matter far less here than for fruiting crops. Mizuna 'Red Kingdom' is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.
How often should I feed mizuna 'red kingdom'?
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. 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. In practice: a balanced or compost-rich start, then a nitrogen side-dress or liquid feed every 3-4 weeks through the cropping period in the main season (spring through early autumn).
What strength of feed for mizuna 'red kingdom'?
Use the vegetable-feed label rate for mizuna 'red kingdom'. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
What does over-feeding mizuna 'red kingdom' look like?
Very soft, floppy, dark-green growth that attracts aphids. Excess leafy growth at the expense of hearts/heads in cabbage and the like. Salt crust and scorched leaf edges in containers; nitrate-heavy leaves. Letting mizuna 'red kingdom' run short of nitrogen mid-crop is the main mistake — growth checks, leaves toughen and brassicas/leafy greens bolt or turn bitter. Keep nitrogen steadily available.
Should I flush the soil of mizuna 'red kingdom'?
For container-grown mizuna 'red kingdom', water until it drains freely each time and flush pots monthly with plain water to stop nitrogen salts accumulating; in the ground, good compost levels naturally buffer this.
Keep reading
- Mizuna 'Red Kingdom' care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water mizuna 'red kingdom' — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise tomato
- How to fertilise pepper
- How to fertilise cucumber
- All 5561 fertilising guides in the Growli library