This naturally occurring iron-potassium silicate (also called glauconite) has the consistency of sand but is able to absorb 10 times more moisture, making it an exceptional soil conditioner for pastures, forage fields, lawns, orchards, small fruits, vegetables and greenhouse potting mixes. Greensand contains potassium, iron, magnesium, calcium and phosphorus plus as many as 30 other trace minerals.
Greensand was deposited millions of years ago when the area was still under water. It is mined primarily for water purification purposes but increasingly more and more people in agriculture and horticulture are requesting it to condition their soil.
Benefits from Greensand are for the most part unexplainable. If you brought some into an ag science lab and asked for an analysis, they would most likely tell you the product is worthless. However, numerous greenhouse trials show that there is a lot more to it than what you might see on a lab report. Organic growers have, for years, extolled the virtues of Greensand without really knowing how or why it has improved their crops.
One possible explanation is mineralization. Studies have shown that mineralizing soil can improve the taste, color, nutritional value and health of various plants as well as the overall health of the soil. Mineralization also improves soil life by increasing populations of certain bacteria that can slowly dissolve insoluble mineral nutrients. Those bacteria eventually cycle themselves into organic matter that further increases populations of many other varieties of beneficial microorganisms.
Greensand has the consistency of sand with a density of approximately 90# per cubic foot (very heavy). It flows like sand and can be applied through any type of spreader, seeder or drill. It can hold one-third its weight in water and has the ability to open tight soils and bind loose soils.
Application rates vary depending on soil conditions and intended use. As a soil conditioner, applications of 25#/1000 ft2 (or 1000#/acre) are recommended. To correct potash deficient soils, anywhere from 20# to 100#/1000 ft2 (or 800# to 4000#/acre) would be applied, depending on the extent of the deficiency.
NOTE: Greensand is a slow release insoluble source of potash and trace elements. If there is an immediate need for available potash, it is suggested that Greensand Plus (a combination of Greensand and Natural Sulfate of Potash with 17 percent soluble potash) or Natural Sulfate of Potash (contains 51 percent soluble potash) be used.
OMRI LISTED™ – View OMRI Certificate
For more information, download the product label pdf.
Greensand – View MSDS (pdf)