pH
/piːˈeɪtʃ/
Definition
Ph measures how acidic or alkaline a solution, soil, or growing medium is. It is a scale based on hydrogen ion concentration, with 7 neutral, values below 7 acidic, and values above 7 alkaline. In plant care, ph describes the root environment because it affects nutrient solubility and uptake. A medium can contain nutrients but still limit absorption if ph is outside the plant’s preferred range.
Practical Relevance
- Nutrient availability: It strongly affects how easily roots absorb minerals. Iron, manganese, and phosphorus can become less available when soil or potting mix is outside a plant’s preferred range, even if nutrients are present.
- Root zone conditions: In containers, hydroponics, and garden beds, shifts can happen through fertilizer salts, alkaline tap water, or limestone-based materials. Regular testing helps explain yellowing leaves, weak growth, or poor uptake.
- Different plant preferences: Some plants, such as blueberries and many azaleas, grow best in acidic conditions, while others tolerate neutral to slightly alkaline soil. Matching the root zone to the plant improves nutrient balance and overall performance.
Related Terms
Soil pH
Soil ph measures how acidic, neutral, or alkaline soil is, based on the concentration of hydrogen ions in the soil…
Soil
Soil is the natural surface layer of land where most plants root and grow. It is a living mixture of mineral particles…
Soil amendment
Soil amendment refers to a material added to soil to change its physical or chemical properties, such as structure…