How Does Pine Straw Affect the Acidity of the Soil?

Pine straw is made from shed pine needles.

Many gardeners add mulches to their gardens to quickly raise or lower soil acidity. Pine straw is an ideal mulching option for gardeners who want to increase water retention without dramatically effecting soil acidity.

Identification

Pine straw is made from the needles of pine trees that are naturally shed during the tree's lifespan. It is a popular mulching option, particularly in the Southeast regions of the United States.

Drawbacks

Some mulching products cause a significant increase or decrease in soil acidity. Pine straw is not one of these products, and therefore it may not be the best choice for immediate soil amendment, as illustrated in a study conducted at Dale Bumpers Small Farms Research Center. Use organic compost or organic peat if you need an immediate increase in soil pH.

Benefits

Some gardeners may not need to significantly alter soil acidity, in which case pine straw is an excellent option. Pine straw decomposes very slowly, which means that it does not actually affect the soil significantly for some time. This makes it an ideal mulching option for gardeners who need to increase water retention while maintaining a balanced soil pH.

References

• University of Missouri Center for Agroforestry: Pine Straw -- A New Mulch for Missouri
• USDA Agricultural Research Service: Effect of Pine Bark, Pine Straw, and Red Oak Wood Mulches on Soil pH
• Landscape-and-Garden: Inorganic Soil Amendments