pH Measurement on Peat-based Substrates vs Peat Alternatives

The measurement tools for substrates in ornamental horticulture are the same, whatever the substrate is: for peat-based, wood fiber, coir, bark and any other peat-alternatives the usual parameters to monitor are EC (Electric Conductivity), salt content, pH, moisture level or also CEC (Cation Exchange Capacity).

What differs is how parameters “behave” in different kind of substrates. The well-known susceptibility to pH fluctuation of wood fiber or coir-based substrates, for example, requires to master the nutrient supply and the irrigation throughout the whole growing season. Peat predictability, instead, allows for once-for-all decisions.

In this table, few highlights on the differences between peat and alternatives to peat.

pH: Difference Between Peat Substrates and Non-Peat-Based Substrates

In ornamental plant production, pH is evaluated in terms of how individual macro-, meso-, and micronutrients behave in the growing substrate or irrigation water. Both excessively low (acidic) and high (alkaline) pH levels can reduce nutrient availability or make certain elements toxic to plants.

For most ornamental substrates, a pH range between 4.0 (for acid-loving plants) and 6.5 is preferred, as the majority of plant species grow best within this interval.

Our article on the importance and effects of pH in ornamental plant production helps understanding why pH is important in ornamental plant production and shows clear pH tables.

The pH of substrates is of great importance to the nutrient uptake of plants because it if it outside the correct range for a specific crop, the nutrient elements are difficult to absorb for plants which can lead to deficiencies. We have created a full section of articles dedicated to Nutrient Deficiencies in Ornamental Plants: Symptoms, Images, Treatment.

Peat is naturally too acidic for many plants to grow well on, and the pH needs to be adjusted with a calcium source which leads to a very stable pH throughout the growing season. Despite this, peat’s buffer capacity is very good.  

Peat alternatives, though, such as coir, wood fiber and bark do not have this natural pH buffer capacity. For this reason, pH can fluctuate throughout the season. The pH can be steered through irrigation and WSF application. To know how to adapt fertilization and irrigation schedule, it is important to take regular pH measurements. 

pH-meters for Ornamental Plants Production

The measurement device to keep track of the pH level of substrate in pots and containers, is the pH meter. Its probe allows for direct measurements in the substrate. A more detailed explanation of this measuring tool as well as EC-meter and ways to monitor substrate’s moisture is given in this article.

Conclusions

The most important take away for plant growers is that regular measurements of less stable growing material such as peat-alternatives can grant crop safety and help avoid plant deficiencies. When one element is not properly absorbed or not supplied in the right quantity, damages occur but, when they are visible, they are difficult to correct. We have prepared an interesting article on nutrient deficiencies in ornamental plants showcasing symptoms, images and treatment when 12 nutritional elements lack.

These subjects might be complex therefore, for personalized guidance, contact your regional technical support by visiting your country’s website or fill in the form you can reach from the banner at the bottom of this page.