In yesterday’s program, Cathy Isom told you about not using rock dust in raised gardens. Today’s program Cathy discusses which rock dust is best for your garden. That’s coming up on This Land of Ours.
Rock dust is most helpful in mineral deficient soil, heavily tilled areas, compacted clay, compost-lite loam soil, and a backyard vineyard. They’re often mined minerals and have varying environmental impacts. Do some research on how they are mined before use.
Azomite is a registered trademark name for a particular kind of volcanic rock. It is said to have 70+ different trace minerals, and is easy to find at most garden centers. If you are concerned about aluminum, lead, and arsenic in soil amendments, do your homework first before buying.
Basalt is a ground form of volcanic rock. Many consider this the best rock dust for vegetable gardens.
Glacial Rock is made from sediment created by glacial expansion and contraction. It may not contain as many trace elements as Basalt or Azomite.
Granite is cheap and the varied particle size means it encourages drainage in clay soils.
Gypsum is a good source of calcium and improves the cation exchange in clay soils.
Some people also use mineral salt to add trace minerals. Coastal plants with high salt tolerance love this stuff.
I’m Cathy Isom…