Quickly Googling 'granite micronutrients' revealed the following: Granite meal (Also called granite dust) Ground granite. 3-5% potassium, 67% silica (sand), and micronutrients. Slow release. One application can last 10 years. Improves soil structure. Broadcast 10 lbs. per 100 sq. ft. on soils low in potassium, 5 lbs. on soils with moderate potassium, and 2.5 lbs. on soils with adequate potassium. Rake into the soil surface. Granite Meal 0-4-0 Micronutrients Very slow release of phosphorus. Will build up reserves in the soil. granite meal (high in K, plus micronutrients); Crushed Granite 0 0 5 Contains 67% silicas and 19 trace minerals. Slow release over a long period of time. Micronutrients: A low level of boron (B) should be corrected with about 5 to 10 lb borax per acre (2-4 ounces/1,000 sq ft) - no more, as some crops are sensitive to too much B. For other micronutrients, moderately low levels can be amended with good compost, seaweed meal or rock powders such as granite dust (check label for micronutrient content). Remember these are micronutrients we are talking about. You don't have to see big chunks dissolving to achieve physiologically relevant concentrations of micronutrients. Of course all of the above and more are subject to the usual physical parameters that will modify availability. J. John T Lonsdale PhD 407 Edgewood Drive, Exton, Pennsylvania 19341, USA Home: 610 594 9232 Cell: 484 678 9856 Fax: 801 327 1266 Visit "Edgewood" - The Lonsdale Garden at http://www.edgewoodgardens.net/ USDA Zone 6b