Fertilising guide

How to fertilise Green Cotton Lavender (Santolina rosmarinifolia)— schedule & NPK

Also called Green cotton lavender, Green santolina, Holy flax, Rosemary-leaved lavender cotton.

More about green cotton lavender

About Green Cotton Lavender

Santolina rosmarinifolia · also called Green cotton lavender, Green santolina · herb

Santolina rosmarinifolia is a compact, evergreen sub-shrub native to the Iberian Peninsula and northwestern Africa, thriving in hot, sunny, and sharply drained Mediterranean conditions. Its fine, needle-like, bright green aromatic foliage is distinctive within the genus, and it bears clusters of bright yellow button flowers in summer. The single most important care rule is excellent drainage: this plant will rot quickly in wet or waterlogged soil, especially over winter. Santolina is not listed on the ASPCA toxic or non-toxic plant database; as its aromatic oils can cause mild GI upset and contact dermatitis in sensitive individuals, treat it as mildly toxic around pets.

Growth habit: Mound-forming, bushy evergreen sub-shrub with an upright to spreading habit.

What fertiliser green cotton lavender actually wants — and why

Green Cotton Lavender is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.

A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed.

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 green cotton lavender: 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 green cotton lavender, 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 green cotton lavender:

Apply a single light dressing of slow-release, low-nitrogen fertiliser in spring; overfeeding produces soft, floppy growth that splits at the centre. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.

The dormant-season rule matters more than the exact interval: skip feeding entirely when green cotton lavender 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 green cotton lavender

Half strength is a sensible default for green cotton lavender — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.

Feeding always goes onto already-damp soil, never dry roots — water green cotton lavender first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the green cotton lavender watering schedule.

Signs you are over-feeding green cotton lavender

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for green cotton lavender:

Fast, soft, pale growth with diluted, less aromatic flavour.
Early bolting (running to flower) and a bitter edge.
Salt crust and scorched tips on container plants.

Signs you are under-feeding green cotton lavender

Pale, slow regrowth after cutting and small leaves.
A tired, stalled plant that cannot keep up with harvesting.
Yellowing older leaves in a long-spent pot.

If the symptoms point at watering, light or roots rather than nutrition, the full green cotton lavender care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Pot-grown green cotton lavender builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.

Organic vs synthetic feeds for green cotton lavender

Organic options

A diluted seaweed feed or worm-casting tea keeps soft growth coming without overdoing it. UK: dilute seaweed or Westland; US: Espoma Garden-tone or Neptune's Harvest. Gentle, hard to overdo, flavour-friendly.

Synthetic / liquid feeds

A balanced liquid feed at half strength through harvesting — UK: Phostrogen, Baby Bio or Westland; US: Miracle-Gro all-purpose at half strength. Fast regrowth; just do not overdo the nitrogen.

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 green cotton lavender — frequently asked questions

What fertiliser does green cotton lavender need?

A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed. Green Cotton Lavender is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.

How often should I feed green cotton lavender?

Apply a single light dressing of slow-release, low-nitrogen fertiliser in spring; overfeeding produces soft, floppy growth that splits at the centre. Apply a single light dressing of slow-release, low-nitrogen fertiliser in spring; overfeeding produces soft, floppy growth that splits at the centre. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.

What strength of feed for green cotton lavender?