What are some good sources of potassium for use by an organic producer?
Sewage sludge is a good source of organic potassium. Because it is not processed, many organic producers consider green sands to be an acceptable potassium source. Manure and wood ashes are also sources of organic potassium. Manure is usually a very good source of phosphorus. Rock phosphate is also a good source of phosphorus, but the phosphorus is in an unavailable form. This will be converted to an available form more quickly in soils that are higher in organic matter or are more acidic.
