What are clear indicators of acidic soil problems?
Written by
Olivia Mitchell
Reviewed by
Prof. Charles Hartman, Ph.D.Acidic soils with a pH of less than 6.0 produce certain distress signaling in your plants that you cannot afford to ignore. The most obvious sign of stress is the presence of yellow leaves with prominent green veins. This indicates that iron is in short supply, as low pH levels lock away essential nutrients needed for healthy vegetative growth and development. The plants appear to be struggling to absorb what they need to grow and develop normally.
A coloration, especially in the foliage of tomatoes and brassicas, that is purple in appearance, shows lock-out of phosphorus in acid conditions. Poor growth in the afflicted plants is frequent because the root system cannot develop properly. In severe cases, such as in the presence of acidity below pH 5.5, the aluminum becomes soluble, and the plant roots are poisoned.
Plant Symptoms
- Yellow leaves with dark green veins signaling iron deficiency
- Purple tinting on leaves indicating phosphorus lockout
- Burned root tips showing aluminum toxicity damage
Growth Issues
- Stunted plant development with small leaves
- Poor fruit set and blossom drop in vegetables
- Reduced flowering in ornamentals like roses
Soil Conditions
- Moss thriving where grass struggles to grow
- Poor decomposition of organic matter
- Increased leaching of calcium and magnesium
Certain plants respond differently to acid soil conditions. Blueberries have red leaves instead of yellow. Tomatoes often develop blossom-end rot due to a calcium deficiency. Conifers may have brown tips. Each of these signs will provide clues about the pH condition of your soil. Tests should be conducted using information that is visible.
Correct acidic soils gradually. Apply lime at the recommended rates based on soil test results. I use organic compost to help naturally buffer the soil pH, re-test after six weeks before planting. Doing so helps prevent the overapplication of lime, which can cause new nutrient imbalances.
Prevent additional acidity issues. Avoid using ammonium-based fertilizers, as they can decrease the pH. Be careful of using pine needle mulch. It is recommended to test your soil annually, and especially after heavy rains. It is essential to maintain pH levels in check, as your plants will not perform optimally without them.
Read the full article: Soil pH Testing: The Complete How-To Guide
