Optimizing Hydroponic EC and pH for the Soilless Production of Calla and Arum Lilies

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Calla lilies (Zantedeschia spp.) and Arum lilies (Zantedeschia aethiopica) are beloved for their stunning blooms and elegant foliage. Traditionally grown in soil, these plants also thrive in hydroponic systems, where managing electrical conductivity (EC) and pH is crucial for optimal growth. This guide explores the best practices for hydroponic cultivation of Calla and Arum lilies, emphasizing the importance of maintaining appropriate EC and pH levels.

Importance of EC and pH in Hydroponics

In hydroponic systems, plants receive nutrients directly through a water-based solution, making the management of EC and pH levels vital.

  • Electrical Conductivity (EC): Measures the concentration of nutrients in the hydroponic solution. Proper EC levels ensure that plants receive the right amount of nutrients.
  • pH: Affects nutrient availability and uptake. Maintaining the correct pH level ensures that plants can absorb nutrients efficiently.

Optimal EC and pH Levels for Calla and Arum Lilies

When growing Arum lilies and Calla lilies in a hydroponic system, managing electrical conductivity (EC) and pH is critical for optimal growth and flower production. Here’s what you need to know:

Optimal EC Levels

  • The nutrient solution’s electrical conductivity should be maintained between 2.0 and 3.0 mS/cm (or dS/m). This range ensures an adequate supply of nutrients without causing toxicity or deficiency issues.
  • Maintaining an EC around 3 dS/m is particularly beneficial for promoting stem length and flower quality.

Nutrient Concentration

  • Higher concentrations of nitrogen (N) and potassium (K) in the nutrient solution are beneficial for Arum and Calla lilies. The nutrient solution should provide a balanced mix of essential nutrients to support vigorous growth and abundant flowering.

Optimal pH Levels

  • The ideal pH range for Arum and Calla lilies in a hydroponic system is between 5.5 and 6.5. Maintaining the pH within this range ensures that essential nutrients remain available and are efficiently absorbed by the plants.
  • A pH of 5.8 is often considered optimal for nutrient uptake and plant health.

Daily Management Practices

Monitoring and Adjusting EC and pH

Regular monitoring and adjustment of the hydroponic solution are essential:

  • Daily Checks: Measure the EC and pH of the solution every morning. Use an EC meter to ensure the nutrient concentration is within the optimal range.
  • Adjustments: Adjust the EC by adding more nutrient solution or water as needed. Use pH adjusters to maintain the pH at the desired level of 5.8.

Hydroponic Systems for Calla and Arum Lilies

Various hydroponic systems can be used to grow these lilies effectively:

Nutrient Film Technique (NFT) System

The NFT system involves a thin film of nutrient solution flowing over the roots of the plants, ensuring they receive a constant supply of nutrients and oxygen.

  • Advantages: Provides excellent oxygenation and nutrient delivery.
  • Disadvantages: Requires careful monitoring to prevent clogging and ensure consistent nutrient flow.

Ebb-and-Flow System

The ebb-and-flow system periodically floods the plant roots with nutrient solution and then drains it away, mimicking natural tidal cycles.

  • Advantages: Ensures thorough nutrient and oxygen delivery.
  • Disadvantages: Requires reliable pumps and timers to manage the flooding and draining cycles.

Growth Conditions

Arum and Calla lilies should be grown in a greenhouse with controlled temperatures ranging from 17.5°C to 30°C and appropriate shading. The nutrient solutions should be recirculated frequently to ensure consistent hydration and nutrient availability. Ensuring the right environmental conditions helps prevent stress and promotes healthy growth.

Maintenance and Monitoring

Regular maintenance and monitoring are essential for the health and productivity of hydroponic Arum and Calla lilies:

  • Daily Monitoring: Daily monitoring and adjustments of the nutrient solution’s EC and pH are essential. Regularly replenishing the nutrient solution volume is necessary to maintain consistency. Using reliable pH and EC meters for monitoring can help ensure accurate readings and timely adjustments.
  • Watering: Ensure the nutrient solution is replenished regularly and the reservoir is kept clean to prevent algae growth.
  • Pest Management: Although hydroponics reduces soil-borne diseases, pests like aphids and spider mites can still affect the plants. Use integrated pest management strategies to control infestations.
  • Pruning: Remove any dead or yellowing leaves to promote air circulation and reduce the risk of fungal diseases.

Results and Benefits

Maintaining higher EC levels, specifically around 3 dS/m, results in better flower production, with more flowers per plant and higher quality stems suitable for commercial purposes. Regular monitoring and adjustments based on these parameters can significantly enhance the growth and yield of Arum and Calla lilies in hydroponic systems.


Growing Arum and Calla lilies in hydroponic systems requires diligent management of EC and pH levels. By maintaining optimal ranges and regularly monitoring the hydroponic solution, gardeners can ensure healthy, vibrant growth and abundant blooms. Hydroponic cultivation not only enhances the aesthetic appeal of these lilies but also demonstrates the efficiency and versatility of soilless growing methods. With the right practices, Calla and Arum lilies can thrive beautifully in any hydroponic setup. Regular monitoring and precise adjustments are key to preventing nutrient imbalances and promoting overall plant health.

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