Aluminum restricts growth by interfering with the metabolism of phosphorus and calcium. It causes stunting and discoloration. Foliage may turn a dull gray green. Aluminum is high in poorly aerated soil and in overly acidic soils.
Make sure your soil doesn’t get compacted by poor watering or lack of compost. Do not allow your soil to become acidic by applying too much sulfur. Soluble calcium helps to reduce the toxicity of aluminum.