Two of the fastest acidifying methods when it comes to soil are white vinegar and coffee grounds. The vinegar should be diluted with filtered water, whereas the coffee grounds should be fresh and tested for an acidic pH before use for the best results.

Mix the sulfur into the soil. For example, if your soil is sandy, add 10 to 20 pounds of elemental S per 1,000 square feet, as sulfur produces a greater reduction in soil pH in a sandy soil than in a loam or clayey soil. Add 40 to 50 pounds of elemental S per 1,000 square feet for clayey soils.

Sulfur for plants is indeed an essential element for their growth, but it’s also used as an agent that acidifies soil.

The cheapest way to lower the soil pH is to add elemental sulfur to the soil. Soil bacteria change the sulfur to sulfuric acid, lowering the soil pH. If the soil pH is greater than 5.5, apply elemental sulfur (S) to decrease the soil pH to 4.5 (see Table 1).

Sulfur can be removed from soils in several ways. Uptake by plants is a major pathway for removal of soil sulfur. Leaching is the second major pathway. Sulfate-sulfur is similar to nitrate-nitrogen, in that both are negatively charged and not held tightly by clay particles (which are also negatively charged).

Some sulfur is beneficial for plants, but if used in excess the sulfur will form excessive salts that can easily kill the plants that you are trying to help. The main concern when the pH is high is that some plant essential nutrients will not be available for uptake by the root system.

Toxicity. Sulfur toxicity for practical purposes should be considered as non-existent. Excessive applications most often result in a depression of soil pH and an increase of the problems that occur with the pH decrease. In fact, sulfur uptake is reduced as the pH of the soil decreases.

Sulfur can burn plants easily if too much is applied. Iron sulfate will react more quickly than elemental sulfur, but you need to add about six times more to get the same change in soil pH. These will add nutrients, as well as lower the pH; however, avoid burning plants by adding too much.

Add Some Vinegar. Vinegar is a mild acid, and adding it to the soil will increase the soil’s acidity. The pH will drop one to two points, depending on how large of an area you water and what type of soil you have.

One of the easiest ways to make soil more acidic is to add sphagnum peat. This works especially well in small garden areas. Simply add an inch or two of peat to the topsoil in and around plants, or during planting.

Once the sulfuric acid is formed, it will react with the calcium carbonate in the soil. If there is enough elemental sulfur to form sulfuric acid and react with all of the carbonate in the soil, the soil pH will continue to decrease over time and stay at the lower pH value in the future.

Sulfur will only work during the warmest months of summer when bacterial activity peaks. It can therefore take up to several months for this method to decrease the soil pH value. Elemental sulfur is the best choice for lowering the pH of very dense soil , such as soils with a heavy clay component.