How to Balance pH for Orchid Cactus

Maintaining the optimal pH range of 5.5 to 6.0 is crucial for the health and growth of an orchid cactus (Epiphyllum). This guide will provide you with a comprehensive understanding of the steps involved in balancing the pH for your orchid cactus, including testing the pH, adjusting the pH, and using the right fertilizers.

Testing the pH

Fertilizing Solution pH

To test the pH of the fertilizing solution, you can use simple and accurate pH test strips. These strips do not require calibration and provide a quick and easy way to measure the pH.

Orchid Mix pH

To test the pH of the orchid mix, you can use the “pour-thru” method. This involves pouring RO (reverse osmosis) water or distilled water through the plant after watering and then testing the resulting leachate for pH using a test strip. This method is gentle on the tender orchid roots and provides an accurate reading of the substrate’s pH.

Adjusting the pH

orchid cactusImage source: Pixabay

Lowering pH

If the pH of the orchid mix is too high, you can lower it by using Citric Acid. Citric Acid is a natural and effective way to acidify the soil, making it more suitable for the orchid cactus.

Raising pH

If the pH of the orchid mix is too low, you can raise it by using Lime or Oyster Shell. These materials are alkaline and will help to increase the pH of the substrate.

It’s important to note that the amount of Citric Acid, Lime, or Oyster Shell needed will depend on the initial pH of the orchid mix and the desired target pH. It’s best to start with small amounts and gradually adjust until the desired pH range is achieved.

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Fertilizers and Water Quality

Rainwater and RO Water

When using rainwater or RO water, which have no dissolved solids, it’s essential to use a fertilizer designed for pure water, such as MSU Orchid Fertilizer. This will prevent the solution from becoming too acidic.

Tap Water

Tap water can vary greatly in its quality and may contain too many dissolved solids. It’s crucial to check the water quality reports, if available, to ensure that the tap water is suitable for your orchid cactus.

Dosage and Application

orchid cactus 2Image source: Pixabay

Citric Acid

When using Citric Acid to lower the pH, start with a small amount, such as 1/4 teaspoon per gallon of water, and gradually increase the dose until the desired pH is achieved. Apply the Citric Acid solution to the orchid mix as needed, typically every 2-4 weeks.

Lime or Oyster Shell

When using Lime or Oyster Shell to raise the pH, start with a small amount, such as 1/2 teaspoon per gallon of orchid mix, and gradually increase the dose until the desired pH is achieved. Mix the Lime or Oyster Shell thoroughly into the orchid mix.

Temperature and Watering Requirements

Orchid cacti thrive in warm, humid environments with temperatures between 65°F and 85°F (18°C and 29°C). Maintain consistent watering, allowing the soil to partially dry out between waterings, and avoid letting the plant sit in water.


Balancing the pH for an orchid cactus is essential for its overall health and growth. By regularly testing the pH of the fertilizing solution and the orchid mix, and adjusting the pH as needed using Citric Acid, Lime, or Oyster Shell, you can create the optimal growing conditions for your orchid cactus. Remember to use the right fertilizers and consider the quality of your water, and maintain the appropriate temperature and watering regimen for best results.

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  1. Orchid Care – Water and pH – rePotme:
  2. Best Soil Potting Mix for Red Orchid Cactus – Greg App:
  3. Growing Orchid Cacti: How to Care for Epiphyllums Indoors – Gardeners Path: