Best Fertiliser for Coleus Plants: Feeding Tips for Bold Foliage Colour

Coleus (Plectranthus scutellarioides) is beloved for its flamboyant foliage—featuring bold patterns in purple, lime, red, and yellow—and its ease of care. Whether you grow coleus indoors in pots or outdoors as bedding plants, the right fertiliser ensures vibrant colour, lush leaf growth, and long-lasting displays.

Coleus Plant Basics – Growth Habit, Colour & Use

Coleus is a tender perennial grown as an annual in most climates. It thrives in shaded gardens, balconies, and indoor spaces where light is bright but indirect. Known for its decorative foliage rather than blooms, coleus responds quickly to proper feeding, pruning, and consistent moisture.

Botanical name: Plectranthus scutellarioides (syn. Solenostemon)
Common names: Painted nettle, flame nettle
Height: 20–60 cm, compact to trailing varieties
Growth type: Annual in cool climates, perennial in frost-free zones
Features: Multicolour leaves; no ornamental flowering needed

Coleus plants are often grown in decorative pots, garden borders, and tropical-themed containers. Their appeal lies entirely in the leaves, so nutrient support must focus on vibrant pigment development and dense branching.

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How to Grow & Maintain Healthy Coleus Plants

Coleus is relatively easy to grow, but its sensitivity to sunlight and moisture levels means it thrives best under partial shade with consistently rich soil. It performs well both in-ground and in containers as long as drainage is sufficient.

Light: Bright shade to filtered light (avoid direct midday sun)
Soil: Rich, well-drained loam or premium potting mix
Watering: Keep evenly moist; don’t allow soil to completely dry out
Humidity: Prefers moderate to high humidity (mist occasionally indoors)
Temperature: Best grown above 15°C; not frost-tolerant

Pinch back growing tips every few weeks to encourage bushier growth. Deadhead insignificant flowers if they appear to focus energy on foliage. In cool climates, take stem cuttings before winter to replant in spring.

For indoor coleus, place near an east-facing window or under grow lights. For outdoor plants, choose locations with dappled morning sun and afternoon shade.

The Best Fertiliser for Coleus Plants

Because coleus is prized for its leaves, the right fertiliser needs to support strong foliage growth without encouraging lanky stems. A balanced fertiliser with equal parts nitrogen (N), phosphorus (P), and potassium (K) works best—especially if it also contains trace minerals that enhance pigment and stem strength.

Nutrient Needs for Coleus

Nitrogen (N): Boosts lush leaf development and vibrant patterns
Phosphorus (P): Supports root stability and general plant health
Potassium (K): Enhances leaf strength, structure, and colour retention
Magnesium & iron: Help maintain green pigmentation and prevent yellowing

Feeding Schedule for Coleus

Spring–Autumn: Feed every 2–3 weeks with a diluted liquid fertiliser
Winter: Pause feeding when growth slows or bring plants indoors
Container plants: Require more frequent feeding than in-ground plants

Recommended product: Use CompleteGrow’s Indoor Plant Food Concentrate. It’s formulated for decorative foliage plants like coleus, delivering complete nutrition in a low-dose formula that prevents leaf burn. Just 1–2 mL per litre is enough to keep leaves vibrant and healthy indoors or out.

Frequently Asked Questions

Can I grow coleus indoors year-round?

Yes. As long as it receives bright indirect light, coleus makes an excellent indoor foliage plant. Use a balanced indoor fertiliser and maintain humidity.

Why are my coleus leaves fading in colour?

Leaf colour fades due to excess sunlight, poor nutrition, or underwatering. Move the plant to shade and feed with a complete NPK fertiliser to restore vibrancy.