Do Ranunculus Need Fertiliser? Feeding & Care Guide

Yes — ranunculus absolutely need fertiliser to thrive. As heavy feeders, they require consistent nutrition to produce strong foliage, sturdy stems, and abundant blooms. Without regular feeding, plants quickly weaken, leaves turn pale or yellow, and flowering is reduced. A well-planned fertiliser routine ensures that each corm reaches its full potential, producing dozens of vibrant flowers during the season. The key is starting with a balanced fertiliser during leafy growth, then switching to a bloom-boosting formula as buds form.

When & How to Fertilise Ranunculus

Fertilising ranunculus is not a one-time task but a steady process throughout the growing season. Their rapid growth cycle means they require both nitrogen for leaves and potassium for flowers. Here’s the best approach:

At planting: Mix a small amount of slow-release fertiliser into the soil to provide an early nutrient base. Avoid high nitrogen at this stage.
Early growth (leaf stage): Apply a balanced fertiliser such as CompleteGrow NPK 20-20-20 every 2–3 weeks. This supports strong root systems and lush foliage, setting the foundation for flower production.
Budding & flowering stage: Switch to NEW Advanced Formula NPK 4-18-38 + Calcium & Magnesium. Its higher potassium content promotes large, colourful blooms while calcium strengthens stems and magnesium enhances leaf health.
Application method: Fertilise with a liquid feed diluted in water for fast uptake. For pots, apply until water runs through the drainage holes. For garden beds, soak the soil evenly around each plant.

Consistency is key — feed regularly during active growth and flowering, but stop fertilising once the foliage begins to yellow naturally at the end of the season. This signals the plant is entering dormancy and no longer needs additional nutrients.

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Why Fertiliser Matters for Ranunculus

Ranunculus corms are energy stores, but they cannot fuel a full season of lush growth and abundant flowering without additional feeding. Fertiliser provides:

Nitrogen (N): Encourages green leaves and photosynthesis, essential early in the growth cycle.
Phosphorus (P): Stimulates root development, helping corms establish quickly.
Potassium (K): Boosts flower size, colour, and longevity, especially important during bloom.
Calcium & Magnesium: Strengthen stems, prevent leaf yellowing, and improve nutrient absorption for more resilient plants.

Without regular fertiliser, ranunculus may produce small or weak flowers, and leaves often yellow prematurely. By following a feeding schedule with NPK 20-20-20 for balanced growth and NPK 4-18-38 + CaMg for flowering, you ensure maximum results from each corm.

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Ranunculus Fertilising FAQs

Do ranunculus need fertiliser?
Yes. Fertiliser is essential for healthy growth and prolific flowering. Without it, plants become weak and flowers are limited.

When should I fertilise ranunculus?
Begin fertilising once shoots appear and continue every 2–3 weeks through the growing and flowering season. Stop once foliage yellows and the plant enters dormancy.

What is the best fertiliser for ranunculus?
Use a balanced fertiliser such as CompleteGrow NPK 20-20-20 during leaf growth, then switch to NPK 4-18-38 + CaMg as buds form for maximum blooms.

Can you over-fertilise ranunculus?
Yes. Too much fertiliser, especially nitrogen, leads to excessive leaves and fewer flowers. Always follow recommended rates.

What happens if I don’t fertilise ranunculus?
Plants will survive but with weak stems, fewer flowers, and shorter bloom times. Fertiliser is the difference between average and spectacular results.

Fertilising ranunculus is the single most important step to ensure strong plants and abundant blooms. With the right feeding schedule and high-quality fertilisers, you can transform each corm into a powerhouse of colour and growth season after season.