How much rock dust is enough? A bit of basalt goes a long way toward improving soil health

Gardeners frequently ask, “How much rock dust should I apply to my garden to get results?” Let us start by saying that not all rock dust is alike and that we cannot speak for other products, only for ours.

But without taking anything away from our competitors, we see Cascade Minerals as an improved replacement over other products that claim to remineralize and regenerate the soil (many of these products are derived from montmorilonite clay).

That’s because all-natural Cascade Minerals Remineralizing Soil Booster is made of finely milled volcanic basalt and nothing more. No man-made additives. No synthetic chemicals. As such, it poses no risks to plants or the environment when applied as directed.

But back to the question at hand: “How much should I add?”

It doesn’t take much crushed volcanic basalt to keep essential micronutrients and trace elements at optimum levels. About 10 pounds of product, raked or lightly tilled into the soil, is enough to cover a 10 x 10 garden (or 100 square feet).

Other suggested application rates are as follows:

  • Trees and shrubs: Approx. 1 cup per 1 inch of trunk diameter spread evenly across rooting area (rake or till into soil if possible, otherwise water in thoroughly)
  • Flowering plants: Approx. 1 cup lightly raked into the soil around plants
  • Lawns: Approx. 10 lbs per 200 square feet of lawn, applied using a lawn spreader or by hand (for best results, apply after aeration)
  • Composts: Approx. 10 lbs per cubic yard, mixed into compost and watered as needed
  • Indoor house plants: Approx. 1-2 cups per gallon of potting soil (mixed prior to planting; for surface applications, use 1-2 tsp per every inch of pot diameter and lightly stir into the top of soil)

Once a sufficient dose has been applied to produce a beneficial plant response, you don’t need to add any more until the following planting season. Basalt is slow-releasing, meaning that it works steadily over time.

If you think that a mid-season mineral boost is in order, however, go ahead and spread a thin layer over your planting beds. But generally speaking, adding more than the suggested amounts won’t result in an exponential burst of growth. And even though you don’t have to worry about damaging your plants or the environment when you use all-natural Cascade Minerals, you’ll be better off saving any extra product for the next time you cultivate your soil or prepare your containers for planting.