Fertilising guide
How to fertilise Napa Cabbage 'Blues' (Brassica rapa var. pekinensis 'Blues')— schedule & NPK
Also called Blues napa cabbage, kimchi cabbage.
More about napa cabbage 'blues'
About Napa Cabbage 'Blues'
Brassica rapa var. pekinensis 'Blues' · also called Blues napa cabbage, kimchi cabbage · edible
Napa cabbage 'Blues' is a heat- and bolt-tolerant F1 Chinese cabbage forming firm barrel heads in about 50-57 days, widely grown for kimchi. Its strong slow-bolting habit lets it cope with warmer or spring sowings better than most napa types. It still wants cool finishing weather, fertile soil and unbroken moisture for sweet, dense heads.
Growth habit: Upright, dense cylindrical (barrel) head of tightly wrapped, crinkled pale-green leaves over broad white midribs; vigorous and uniform.
Watch for — Tip-burn: Brown, scorched inner-leaf margins from uneven calcium uptake during rapid heading. Water consistently, hold pH near neutral and avoid pushing soft, fast nitrogen growth.
What fertiliser napa cabbage 'blues' actually wants — and why
Napa Cabbage 'Blues' 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 napa cabbage 'blues': 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 napa cabbage 'blues', 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 napa cabbage 'blues':
Heavy feeder. Enrich with compost and side-dress nitrogen as heading begins. Even calcium and potassium firm the head and limit tip-burn; avoid late nitrogen excess that loosens heads. 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 napa cabbage 'blues' 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 napa cabbage 'blues'
Use the vegetable-feed label rate for napa cabbage 'blues'. 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 napa cabbage 'blues' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the napa cabbage 'blues' watering schedule.
Signs you are over-feeding napa cabbage 'blues'
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for napa cabbage 'blues':
- 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 napa cabbage 'blues'
- 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 napa cabbage 'blues' care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
For container-grown napa cabbage 'blues', 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 napa cabbage 'blues'
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 napa cabbage 'blues' — frequently asked questions
What fertiliser does napa cabbage 'blues' 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. Napa Cabbage 'Blues' 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 napa cabbage 'blues'?
Heavy feeder. Enrich with compost and side-dress nitrogen as heading begins. Even calcium and potassium firm the head and limit tip-burn; avoid late nitrogen excess that loosens heads. Heavy feeder. Enrich with compost and side-dress nitrogen as heading begins. Even calcium and potassium firm the head and limit tip-burn; avoid late nitrogen excess that loosens heads. 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 napa cabbage 'blues'?
Use the vegetable-feed label rate for napa cabbage 'blues'. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
What does over-feeding napa cabbage 'blues' 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 napa cabbage 'blues' 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 napa cabbage 'blues'?
For container-grown napa cabbage 'blues', 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
- Napa Cabbage 'Blues' care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water napa cabbage 'blues' — 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