Fertilising guide

How to fertilise Lacinato Kale (Brassica oleracea var. palmifolia 'Lacinato')— schedule & NPK

Also called Lacinato kale, Tuscan kale, dinosaur kale, cavolo nero, black kale.

More about lacinato kale

About Lacinato Kale

Brassica oleracea var. palmifolia 'Lacinato' · also called Lacinato kale, Tuscan kale · edible

Lacinato kale, also called Tuscan or dinosaur kale, is an Italian heirloom with long, narrow, deeply puckered blue-green leaves on an upright stem. It is one of the most cold-hardy kales, sweetening after frost, and can stand through winter in mild areas. A heavy-feeding, cool-season biennial grown as an annual, it tolerates heat better than most kales but is at its sweetest in cool weather.

Growth habit: Upright, non-heading biennial grown as an annual, producing a single thick stem topped by a rosette of strappy leaves; harvest lower leaves and it keeps growing from the crown.

Watch for — Clubroot: Stunted, wilting plants with swollen, distorted roots in infected brassica soil. Rotate crops, lime to near-neutral pH and improve drainage; the spores persist for years.

What fertiliser lacinato kale actually wants — and why

Lacinato Kale is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.

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 lacinato 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 lacinato 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 lacinato kale:

A hungry leafy brassica. Dig in plenty of compost or aged manure before planting and side-dress or liquid-feed with a nitrogen-rich fertiliser every 3-4 weeks through the growing season for continuous leaf production. 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 lacinato 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 lacinato kale

Use the vegetable-feed label rate for lacinato 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 lacinato kale first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the lacinato kale watering schedule.

Signs you are over-feeding lacinato kale

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for lacinato 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 lacinato 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 lacinato kale care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

For container-grown lacinato 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 lacinato 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 lacinato kale — frequently asked questions

What fertiliser does lacinato 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. Lacinato 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 lacinato kale?

A hungry leafy brassica. Dig in plenty of compost or aged manure before planting and side-dress or liquid-feed with a nitrogen-rich fertiliser every 3-4 weeks through the growing season for continuous leaf production. A hungry leafy brassica. Dig in plenty of compost or aged manure before planting and side-dress or liquid-feed with a nitrogen-rich fertiliser every 3-4 weeks through the growing season for continuous leaf production. 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 lacinato kale?