How does acidic soil affect plant nutrients?

The acidity of soil fundamentally affects the availability of plant nutrients in many complex ways. Specifically, when soil pH is below 5.5, the solubility of certain minerals can change substantially. These changes in chemical composition lead to both strengths and weaknesses for the gardener. To grow healthier plants in acidic soils, it is important to be aware of these changes.

Aluminum toxicity can have serious implications in extremely acidic soils. When pH levels drop below 5.0, aluminum in the soil dissolves into forms that are available to plants. This can cause damage to the roots and limit the volume of water that can be absorbed. Common symptoms include stunted growth and a purplish coloration. Acidophilic plants, or those that prefer to live in low pH soils, have adaptations to tolerate aluminum toxicity.

Phosphorus lockup creates challenges relating to nutrition. This important nutrient binds tightly to aluminum and iron under acidic conditions or at low pH levels. Even in the presence of fertilizer applications, plants cannot access the phosphorus. Bone meal should be considered, as it remains available to plants at pH levels below 6.0. Foliar sprays offer an alternative; phosphorus can be absorbed from foliage.

You should take care to treat a deficiency of calcium and magnesium. Gypsum is a way to add calcium without increasing pH. Epsom salt can be used for magnesium. Calcium and magnesium play a crucial role in preventing blossom end rot and yellowing leaves. Annual soil testing is recommended to maintain a proper balance.

Monitor micronutrient deficiencies and excesses. Iron and manganese are highly soluble below a pH of 5.5. This level is beneficial for blueberries, but may be excessive for other species. Chelated supplements are a good place to start, and they provide controlled-release application. Regular soil testing will help you determine what you must supplement and how much.

Read the full article: 10 Acidic Soil Plants That Thrive