Macronutrient - Potassium (K) is used in relatively large amounts by plants. It helps in photosynthesis, building of protein, fruit quality and in the resistance to disease.

Sources - This element comes from the soil, organic matter and fertilizers.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.