How Much Sulfur to Add to Soil for Blueberries

Test

• Check the actual acidity of the soil before you add anything. You can pay to have a soil sample tested at a cooperative extension office. The extension office will give you a full report of the condition of your garden soil, far more than just the acidity levels. Another simple way is to purchase a pH indicator that you simply poke into the soil to get a reading.

Type of Sulfur

• Sulfur will drop the pH of the soil more quickly than other amendments. You can purchase it as aluminum sulfate to sprinkle over the soil, but this method tends to slowly make the soil toxic from the aluminum, and eventually the roots in the vicinity will die. Elemental sulfur is a better amendment, but even though it might be the fastest amendment, you still might need a couple of years to get the soil to a stable acidity suitable for blueberries.

Amount

• You can calculate the amount of elemental sulfur you need to grow your blueberries by using what the industry calls a clay chart. The higher the amount of clay, the more elemental sulfur you would add. You cannot add more thinking that extra will work more quickly, as the soil could become toxic to any plant growth for a few years.

Method

• Even if you figure out the existing pH of your soil and then use the clay chart to determine how much elemental sulfur you need, you must work it into the soil. Changing the pH of the soil takes working the amendment down into the top 6 inches of soil or more so that the roots of the soil can access it. The elemental sulfur reacts with bacteria in the soil and forms sulfuric acid, acidifying the soil.