Some humus materials will also lower the pH of soil.
- Sphagnum peat moss is acidic (see pH scale), and lowers the pH of soil in which it is mixed. Fifty to one hundred pounds of sphagnum peat moss per 1,000 square feet of soil is required to lower the pH about one point.
Sphagnum Peat Moss
Sphagnum peat moss can be purchased by the cubic foot. The current price in Denver, Colorado is $8.50 for a 3.8 cubic foot--compressed.
- Pine bark is also acidic and if prepared properly and mixed into
the soil will also lower the pH of the soil. To decompose in a
reasonable time frame, it must be shredded to a very small size. It
is typically referred to as "pine bark soil conditioner."
The current price in Longmont, Colorado is $4.25 for 2 cubic foot.
Chipped Pine Bark
Pine Bark Soil Conditioner
Partially Composted