Ground Covers: Iron Deficiency

Problem
Leaves turn pale green or yellow. The newest leaves (those at the tips of the stems) are most severely affected. Except in extreme cases, the veins of affected leaves remain green. In extreme cases, the newest leaves are small and all-white or yellow. Older leaves may remain green.

Analysis
Plants frequently suffer from deficiencies of iron and other minor nutrients such as manganese and zinc, elements essential to normal plant growth and development. Deficiencies can occur when one or more of these elements are depleted in the soil. Often, minor nutrients are present in the soil, but alkaline (pH higher than 7.0) or wet soil conditions cause them to form compounds that cannot be used by the plant. An alkaline condition can result from overliming, or from lime leached from cement or brick. Regions where soil is derived from limestone, and those with low rainfall, usually have alkaline soils.

Solution
Spray the foliage with a chelated iron fertilizer, and apply it to the soil around the plants to correct the deficiency of minor nutrients. Check the soil pH (see the instructions in Soil Testing). Correct the pH of the soil by treating it with ferrous sulfate or aluminum sulfate and watering it in well. Maintain an acid pH by fertilizing with an acid-reaction fertilizer.