If you search online for “What is pH?”, you’ll likely find a scientific definition:
pH is a scale from 0 to 14 that measures how acidic or basic a solution is, with 7 being neutral, below 7 acidic, and above 7 alkaline. Each whole number represents a tenfold change in strength.

While accurate, this definition doesn’t tell growers what really matters: pH directly influences nutrient availability and plant health. Poor pH management can lead to serious problems in the root zone and ultimately reduce yield and quality.

Why pH matters for growers
pH determines how easily plants can absorb nutrients. If the pH is too low or too high, certain elements become unavailable, causing deficiencies even when nutrients are present in the solution. But also other topics related to pH are important. pH also has influence on precipictation of fertilizers in the dripping system and influence on pathogens.

What influences pH?
Several factors affect pH in irrigation water and substrate:

• Bicarbonates in source water: High levels (common in areas with limestone) increase pH and require neutralization with acids.
• Rainwater: Contains no bicarbonates and reacts differently when fertilizers are added.
• Fertilizers: Some nutrients, like ammonium (NH₄⁺), strongly influence pH.
• Irrigation strategy: Substrate refreshment and dry-back also impact pH stability.

Managing pH: practical guidelines

1. Know your water source: Test bicarbonate levels before the season starts. 
   • Example: Water with 3 mmol/L bicarbonates requires 3 mmol/L nitric or phosphoric acid to neutralize.
2. Set target pH levels: Aim for around 5.5 in the root zone for optimal nutrient uptake.
3. Monitor regularly: Check pH at the dripper and in the slab—not just in drain water.
4. Adjust carefully: Remember that adding acid also adds nutrients (N or P), which must be factored into your overall fertilization plan.
5. Adapt to conditions: 
   • Low light periods → slightly higher EC and stable pH to maintain generative growth.
   • High light periods → lower EC and controlled pH to support transpiration and nutrient uptake.

Cultilene solutions: your partner in pH management
At Cultilene, we know that pH control is not just a technical detail—it’s a cornerstone of successful cultivation. Our technical specialists help growers interpret water analyses, set seasonal targets, and design irrigation strategies that keep pH stable throughout the crop cycle. Combined with our high-quality stone wool substrates, which maintain uniform water and nutrient distribution, we provide a complete approach to root zone management. By integrating data-driven advice with practical solutions, we help you prevent structural issues, optimize nutrient availability, and maintain plant balance under varying conditions.

Summary: pH management is essential for healthy roots and predictable growth. By understanding your water source, setting clear targets, and monitoring regularly, you can avoid costly mistakes and ensure your crop thrives.

The information provided by Saint-Gobain Cultilene has been compiled with great care and is intended solely as a guideline for the user. Saint-Gobain Cultilene therefore cannot guarantee any errors and no rights may be derived from the information or advice provided. The user himself is responsible for checking the accuracy and suitability of the information and advice for application. No commercial use may be made of the information and advice provided by Saint-Gobain Cultilene, in whole or in part, without the written consent of Saint-Gobain Cultilene.