Fertilising guide
How to fertilise 'January King' Cabbage (Brassica oleracea var. capitata 'January King')— schedule & NPK
Also called January King winter cabbage.
More about 'january king' cabbage
About 'January King' Cabbage
Brassica oleracea var. capitata 'January King' · also called January King winter cabbage · edible
January King is a classic, extremely hardy winter cabbage forming a dense, drum-shaped head with crinkled blue-green outer leaves flushed purple-red in cold. Sown in late spring, it stands in the ground through autumn and winter to harvest from late autumn into late winter. It needs full sun, firm fertile soil and a long, cool season, rewarding patience with a sweet, frost-kissed head.
Growth habit: Robust, ground-hugging cabbage that builds a broad rosette of spreading outer leaves before folding inward to form a single dense, flattened-drum head that stands well through winter.
Watch for — Clubroot: Soil-borne disease swelling and rotting roots, stunting plants over the long season. Lime to near-neutral pH, improve drainage, and rotate brassicas on a 3-4 year cycle.
What fertiliser 'january king' cabbage actually wants — and why
'January King' Cabbage 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 'january king' cabbage: 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 'january king' cabbage, 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 'january king' cabbage:
Hungry feeder. Incorporate a balanced fertiliser before planting and side-dress with nitrogen as plants establish to build a strong leafy frame. Ease off feeding once heads start to firm and avoid heavy nitrogen in mid-winter. 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 'january king' cabbage 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 'january king' cabbage
Use the vegetable-feed label rate for 'january king' cabbage. 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 'january king' cabbage first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the 'january king' cabbage watering schedule.
Signs you are over-feeding 'january king' cabbage
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for 'january king' cabbage:
- 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 'january king' cabbage
- 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 'january king' cabbage care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
For container-grown 'january king' cabbage, 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 'january king' cabbage
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 'january king' cabbage — frequently asked questions
What fertiliser does 'january king' cabbage 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. 'January King' Cabbage 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 'january king' cabbage?
Hungry feeder. Incorporate a balanced fertiliser before planting and side-dress with nitrogen as plants establish to build a strong leafy frame. Ease off feeding once heads start to firm and avoid heavy nitrogen in mid-winter. Hungry feeder. Incorporate a balanced fertiliser before planting and side-dress with nitrogen as plants establish to build a strong leafy frame. Ease off feeding once heads start to firm and avoid heavy nitrogen in mid-winter. 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 'january king' cabbage?
Use the vegetable-feed label rate for 'january king' cabbage. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
What does over-feeding 'january king' cabbage 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 'january king' cabbage 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 'january king' cabbage?
For container-grown 'january king' cabbage, 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
- 'January King' Cabbage care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water 'january king' cabbage — 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 1284 fertilising guides in the Growli library