In use for over 50 years as a source of available potash (0.2%) and over 50 trace minerals, including calcium (1.8%),sodium (0.1%), and magnesium (0.5%). 1 lb does 10 square feet.
$1.50 – $30.00
Grower: Morgans Composting
This fertilizer (described in Secrets of the soil as “rock dust”) is mined from an ancient deposit of aluminum silicate clay and marine minerals.