Probably the most confusing material is Dolomite. Often it's not labeled as Dolomite, but don't give up, you can find it if you look a little. Dolomite is commonly sold in garden or farm stores.
Dolomite is added to the potting mix to:
1) adjust the pH : it lowers the acidity ("sweeten")
2) add magnesium (important!)
3) add calcium (important!)
Key Points When Shopping for Dolomite:
-Often the bag will NOT say "dolomite"
-It might be labeled as "Agricultural Lime", "Agricultural Limestone" or "Garden Lime". Check the ingredients label. It must have CALCIUM & MAGNESIUM.
-"Agricultural Lime" and "Garden Lime" are broad terms. Just remember, if it doesn't say calcium, magnesium or calcium/magnesium carbonate or some variation of this, then it's not dolomite.
-"Hydrated Lime" is not dolomite. Hydrated Lime is highly concentrated, highly caustic and dangerous to handle or breath. Also, it contains no magnesium.
-Any bag of "lime" labeled "DOLOMITE" containing calcium and magnesium is suitable.
-Dolomite can be sold in finely powdered, pulverized or pelleted form. Buy the powdered or pulverized and avoid the pelleted form. The finer the dolomite is ground, the faster it becomes available to the plants. Talcum powder fine is best.
-Price: For a 50lb bag the cost should be US $4.00 to US $6.00
-Acid loving plants, like strawberries or blueberries, only need 1/2 cup or less.