Fertilising guide
How to fertilise 'Red Russian' Kale (Brassica napus var. pabularia 'Red Russian')— schedule & NPK
Also called Red Russian kale, Ragged Jack kale.
More about 'red russian' kale
About 'Red Russian' Kale
Brassica napus var. pabularia 'Red Russian' · also called Red Russian kale, Ragged Jack kale · edible
Red Russian is a tender, frilled, flat-leaved kale with grey-green oak-shaped leaves and purple-red stems and veins that intensify in cold. Botanically a Brassica napus type, it is milder and more delicate than curly kale, excellent as both baby leaf and mature greens. Very cold-hardy and quick to crop, it tolerates poorer soils than most brassicas.
Growth habit: Open, spreading, non-heading kale with tender, flat, deeply lobed oak-leaf foliage on slender red-purple stems; forms a loose rosette and resprouts readily when leaves are cut.
What fertiliser 'red russian' kale actually wants — and why
'Red Russian' Kale 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 'red russian' kale: 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 'red russian' kale, 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 'red russian' kale:
Moderate feeder. Mix a balanced fertiliser into the bed before planting and side-dress with a nitrogen feed every 4-6 weeks during active growth. Cut-and-come-again baby-leaf crops benefit from a liquid feed after each harvest. 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 'red russian' kale 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 'red russian' kale
Use the vegetable-feed label rate for 'red russian' kale. 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 'red russian' kale first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the 'red russian' kale watering schedule.
Signs you are over-feeding 'red russian' kale
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for 'red russian' kale:
- 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 'red russian' kale
- 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 'red russian' kale care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
For container-grown 'red russian' kale, 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 'red russian' kale
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 'red russian' kale — frequently asked questions
What fertiliser does 'red russian' kale 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. 'Red Russian' Kale 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 'red russian' kale?
Moderate feeder. Mix a balanced fertiliser into the bed before planting and side-dress with a nitrogen feed every 4-6 weeks during active growth. Cut-and-come-again baby-leaf crops benefit from a liquid feed after each harvest. Moderate feeder. Mix a balanced fertiliser into the bed before planting and side-dress with a nitrogen feed every 4-6 weeks during active growth. Cut-and-come-again baby-leaf crops benefit from a liquid feed after each harvest. 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 'red russian' kale?
Use the vegetable-feed label rate for 'red russian' kale. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.
What does over-feeding 'red russian' kale 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 'red russian' kale 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 'red russian' kale?
For container-grown 'red russian' kale, 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
- 'Red Russian' Kale care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water 'red russian' kale — 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