Phalaenopsis Orchid Care Guide | How to Grow & Fertilise Moth Orchids in Australia

Phalaenopsis orchids, also known as Moth Orchids, are Australia’s most popular indoor orchid. Recognised for their elegant arching stems and long-lasting blooms, they can flower for several months at a time. With the right care, these orchids will thrive and rebloom year after year.

Why Choose Phalaenopsis Orchids?

Easy to maintain indoors with bright, indirect light
Flowers can last 6–12 weeks and rebloom with proper care
Well suited to Australian homes and office environments
Adaptable to warm, humid conditions

Growing Conditions

To achieve consistent growth and repeat flowering, focus on four essentials:

Light: Provide bright, indirect light. Avoid harsh afternoon sun, which can scorch leaves.
Temperature: Maintain a range between 18–28°C. Protect from cold drafts in winter.
Watering: Water when the orchid bark feels nearly dry. Do not allow roots to sit in water.
Humidity: Maintain moderate humidity with a pebble tray or light misting in dry conditions.

Repotting

Phalaenopsis orchids should be repotted every one to two years into fresh orchid bark. This process:

Refreshes the growing medium and improves aeration
Prevents root rot by removing decayed material
Supports healthy new growth and root development

Tip: The best time to repot is immediately after flowering. Trim away dead or damaged roots before settling the plant into fresh medium.

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Fertiliser Needs & Feeding Schedule

Feeding is essential for strong growth and reliable flowering in Phalaenopsis orchids. Without proper nutrition, plants may develop pale leaves, produce smaller flowers, or fail to bloom. A balanced fertiliser that contains nitrogen, phosphorus, potassium, and trace elements is ideal for sustained health.

When and How to Feed

Spring and Summer: Apply fertiliser weekly in diluted amounts to support active growth and flower spike development.
Autumn: Reduce feeding to every two weeks as the plant slows its growth.
Winter: Fertilise monthly to maintain leaf health while the plant rests.

The “weakly, weekly” method is widely recommended: apply a diluted liquid fertiliser each week during the growing season. Flush the pot with plain water once a month to prevent fertiliser salts from building up in the medium.

Choosing the Right Fertiliser

Balanced, water-soluble fertilisers are the most effective for orchids grown indoors. Many growers switch to a higher-phosphorus formulation when flower spikes appear, as this encourages strong and lasting blooms. Avoid over-fertilising, which can damage delicate roots and reduce flowering performance.

Tip: Consistency is more important than strength. Regular light feeding will always outperform heavy, irregular applications.

For Australian homes, a practical choice is CompleteGrow Indoor Plant Food Concentrate. This balanced liquid fertiliser provides the right nutrient profile for Phalaenopsis orchids, supporting both foliage growth and extended flowering. It is ideally suited to the “weakly, weekly” approach that keeps orchids healthy year-round.

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Common Problems & FAQs

Phalaenopsis orchids are generally hardy, but they can develop issues if care practices are inconsistent. Identifying the cause early allows growers to make quick adjustments and restore plant health.

Frequent Issues

Yellowing Leaves: Usually caused by overwatering, low light, or nutrient deficiency.
Wrinkled Leaves: A sign of under-watering or dry air conditions.
Root Rot: Caused by soggy, compacted potting mix or poor drainage.
Lack of Flowers: Often due to insufficient light or inconsistent feeding.

Tip: After flowering, trim the spike just above a node to encourage a secondary bloom. If the spike turns brown, cut it back to the base and allow the plant to rest before the next flowering cycle.

Frequently Asked Questions

How do you care for a Phalaenopsis orchid? Provide bright, indirect light, moderate watering, and maintain humidity. Repot every one to two years and feed regularly with a balanced liquid fertiliser such as CompleteGrow Indoor Plant Food Concentrate.

How to replant a Phalaenopsis orchid? Repot into fresh orchid bark after flowering. Trim away any dead or damaged roots, choose a slightly larger pot, and stabilise the plant in the new medium.

Why is my Phalaenopsis not flowering? The most common causes are lack of light and insufficient feeding. Ensure the plant receives bright filtered light and a phosphorus-rich fertiliser during spike development.

Can I use liquid fertiliser on Phalaenopsis orchids? Yes, liquid fertilisers are highly effective when diluted and applied consistently. They provide a steady nutrient supply that supports both healthy foliage and repeated flowering.

By maintaining the right balance of light, water, and nutrition, Phalaenopsis orchids will continue to reward growers with striking blooms that last for months. With consistent care and the right fertiliser, these orchids can thrive in Australian homes for many years.