How can I increase potassium in soil to improve plant growth and health?

To increase potassium in soil for better plant growth and health, you can use potassium-rich fertilizers like potassium sulfate or potassium chloride. Additionally, adding organic matter such as compost or manure can help improve potassium levels in the soil. Testing the soil regularly and adjusting the fertilizer application based on the results can also help maintain optimal potassium levels for plant growth.