As your garden grows each year, the minerals that are native to your soil are depleted and need to be replenished. Adding rock dust to your garden is a natural and easy to use soil amendment and is a great way to add trace minerals and micronutrients to your soil. 

Rock dust can be made of any kind of mined rock that is ground to a powder and is also sometimes called rock flour, rock minerals, rock powder, stone dust, soil remineralizer, and mineral fines. 

Not only does rock dust add trace minerals and micronutrients to replenish your soil, it feeds the beneficial microbes that live in your soil, and also increases the Cation Exchange Capacity, or CEC, of your soil.

However, not all rock dusts are alike, so it’s important to know which one to use. It is true that all rock dusts provide minerals for your soil, but different rocks are made up of different minerals. Getting a complete soil analysis done on your soil can help you determine which type of rock dust is best suited for your needs. Rock dusts cannot burn your plants’ roots, so there is never any risk of over-application. However, applying more than the product directions indicate will not provide any additional benefit to your plants or soil. The minerals it provides are only needed in small amounts, and there is a natural limit on how much can be utilised at once and how fast it will be used up.

There are three primary sources for rock dust: 

• Basalt rock dust is made of volcanic rock and is usually a by-product of mining. It is considered by most gardeners to be the most environmentally friendly form of rock dust as there is little to no risk of heavy metal contamination.
• Glacial rock dust is made from rocks deposited by glacial action and contains a wide variety of rocks left behind as the glacier moved across the landscape. It contains a complex blend of minerals.
• Azomite is only available from one mine in central Utah and is the product of volcanic ash being spewed into a seabed millions of years ago. After the water dried up the resulting ash-and-marine muck turned into rock. It contains the widest range of minerals of all the rock dusts.

Whichever product you’re planning on using to feed your garden this year, don’t forget about adding rock dust!