Most acid-loving plants have a preference for slightly acidic soil over highly acidic ones. If your soil is too acidic to support plant growth, you can make it less acidic by mixing in some lime, compost mix, or wood ash. This process is known as soil alkalization. If you’d like to make your neutral or alkaline soil more acidic, commonly recommended options include the use of peat moss, pine needles, or sulfur. More short-term options include the addition of vinegar. Make sure you take the pH of the soil beforehand. You should also read guides that tell you how much alkalizing or acidifying agents you need to get the level of acidity you desire.