Pine needles & Peatmoss are good untill they are composted then they are 6.5 or 7.0 pH.
If your soil is 4.5, 5.0, or 5.5, you do not need to add sulfur.
Why Lower Soil pH? Some plants (such as blueberries or azaleas) are adapted to grow in acid soils — even as low as pH 4.5. If you are trying to grow them you may want a soil pH less than 6, but remember that even acid-loving plants have their limits. Photo by Phillip Owens, Purdue Agronomy Table 1. Effects of soil amendments on pH. Amendment Effect Biological Reactions Organic matter The reduction in pH is due to microbial degradation and production of organic acids. Large amounts are required. Ammonium fertilizers A comparatively minor effect on soil pH when used in appropriate amounts as a nitrogen fertilizer. Diammonium phosphate, monoammonium phosphate, and ammonium sulfate have more acidic potential than urea or ammonium nitrate. Calcium nitrate and potassium nitrate increase soil pH so should be avoided if pH is already too high. Elemental sulfur (S) Creates acidity as bacteria form sulfuric acid from elemental sulfur. Nonbiological Reactions Aluminum sulfate (Al2 (SO4 ) 3 ) and iron sulfate (FeSO4 ) Chemical reactions create acidity, therefore less temperature dependent than for biological reactions.
https://www.extension.purdue.edu/extmedia/ho/ho-241-w.pdf
