Glacial Rock Dust

As the name implies, glacial rock dust is the pulverized powder that is created after a glacier grinds its way through a rock formation. This rock dust is mined from glacial deposits. Additionally, it tends to contain a wide range of trace minerals essential for healthy soil.

These minerals are often depleted in soil over time. It is very similar to how a tea bag loses its potency after it’s been used five or six times. Adding glacial rock dust helps restore these mineral imbalances. This is done by putting them in an easy access form for soil microbes to break apart. Thus, allowing them to be simple for plant roots to absorb.

When ground into a fine powder and added to vegetable or flower gardens, the minerals in the dust become accessible to the plant roots. Even more so, they help them to increase the number of nutrients they can pull up throughout the growing season.

Though it may just have entered the organic gardening scene in recent years, glacial rock dust has been produced naturally on this planet long before the invention of agriculture.

Thousands of years ago during the last ice age, massive glaciers crossed the country at a creeping pace and ground up giant boulders and other rocky debris along the way. Once the glaciers stopped moving, they deposited their collections into massive piles, called glacial moraines.

Today, these moraines are mined as treasure troves of mineral-rich material. Because glaciers weren’t picky about the type of rocks they picked up, glacial moraines are filled with a wide variety. Each containing a healthy assortment of natural minerals that can benefit your garden soil.

There are plenty of benefits that glacial rock dust can cause for the soil. Here are the three main ways it can help:

Restoring Degraded Soil

In the natural world, when plants and other organisms die their bodies are returned to the soil. Thus, it restores the minerals contained in their bodies back to the ground they lived in. This doesn’t happen in an agricultural situation. Instead, millions of tons of plant matter are taken off farm fields and transported long distances away for resale. This means that the minerals from agricultural soil end up either in septic systems or landfills. Therefore, causing the garden soil to become chronically depleted of minerals with no natural way to have their levels restored.

Glacial rock dust can restore this deficit as it helps to recreate the colloids (minerals and soil structure) within your garden. Thus, making it better suited for retaining moisture, housing beneficial bacteria and making nutrients accessible. Adding rock dust to the soil restores the balance needed for multiple life forms to thrive. Therefore, allowing your plants to be better supported and grow more robust.

Increasing Fruit and Vegetable Nutrition

When soil gets depleted, it loses a lot of its nutritional value. In fact, missing minerals in our food is a huge cause for concern. Though organic compost can restore soil structure, it won’t be able to fix mineral deficiencies in the soil.

Mineral deficiencies don’t just affect the soil, they also affect the quality of our food. Fruits and vegetables grown in degraded soil are missing key minerals. This means that grocery store produce is probably a lot less healthy for you than you actually think. In fact, recent studies show that the vitamin and mineral content in commercially produced fruits and vegetables has been halved in the past four decades. Some agricultural soils are now so deficient that you would have to eat five apples today to get the same nutritional benefit as one apple from 1965! Though this may only seem like an inconvenience, it can have major ramifications for your overall health and well being.

Not only does re-mineralizing soil make plants healthier, it also transfers the benefits to us when we eat them.

Increases Plant Growth and Pest Resistance

Silicate rocks contain an enormous about of minerals and trace elements that keep plants growing well, many of which aren’t contained in commercial fertilizers. This means that adding glacial rock dust to your soil helps your garden plants consume a more well-rounded diet that leads to overall better growth. Some studies have shown growth increases in re-mineralized soils that are up to four times as much as regular soil, and plants ranging from grasses to trees are all positively affected.

Better growing plants also tend to be healthier plants, and garden beds treated to some glacial rock dust often enjoy increased resistance to insect pests and fungal diseases.

Most people add glacial rock dust to their gardens in the spring before planting. However, some of the best benefits come when you apply it in the fall at the end of the growing season. This allows it to assimilate itself into the soil all winter long. Therefore, providing the best benefits for plants in the spring.

Application rates will vary depending on your soil quality and level of mineral depletion. However, a good rule of thumb is that you can apply about 10 pounds of rock dust per 100 square feet of garden space. Then, plant a fall cover crop on top of this. Another idea is to add the dust to your compost pile in order to help it along.

Lawns can also benefit from re-mineralization through rock dust, though you need far less to get good results, usually around 10 pounds per thousand square feet.