To lower pH in potting media (typically unnecessary), see the Potting Media Calculation page.
CORRECTING SULFUR DEFICIENCIES
NOTE: Most labs test for sulfate sulfur (S) and do not include in their findings the S that exists in organic matter. Typically, crops grown in soils with 5% or more organic matter do not require additional S. Moreover, applications of sulfate materials, such as sulfate of potash, langbeinite, gypsum, and Epsom salt, provide plant available sulfur. Sulfate of potash contains 18% S, langbeinite contains 23% S, gypsum contains 19% S, and Epsom salt contains 13% S. To convert S/acre recommendations to sulfate (SO4)/acre application, multiply the S needs by 3. There is 3.2% sulfur in Bud Bread and 6.0% in Coming of Age; however, none of the products mentioned above should be used solely to correct sulfur deficiencies. Elemental sulfur is available from Extremely Green Gardening Co.
If organic matter is <4%, use the following table to determine application rates (expressed in pounds of S/acre):
To determine pounds S/1,000 ft3, divide by 43.56