Volcanic Rock Dust

volcanic rock dustWhen it comes to organic gardening, the health of your plants is only half the story. Equally important is the quality of soil that you grow them in. Successful organic gardens need to have fertile soil filled with organic material. Even more so, a healthy balance of minerals that slowly break down. This keeps the roots of your plants well nourished for maximum plant health.

One of the best ways to restore your garden soil for your plants is to frequently re-mineralize your beds. Plus, it will make it as nourishing as possible too! While plants have plenty of talents, one thing that they can’t do is produce their own necessary minerals. Thankfully, nature does much of the difficult work for us through natural events like volcanoes, glaciers and floods. However, if waiting for the next local volcanic eruption doesn’t fit your time frame, adding mineral supplements to your garden beds is an equally great way to improve your soil fertility.

If you are interested in improving your soil through the use of high quality mineral supplements, read on to learn about the benefits that volcanic rock dust it can create for your plants.

What is Volcanic Rock Dust?

Often going by the names rock flour, rock powder, stone dust and basalt, volcanic rock dust is one of the best things that you can add to your garden. Rock minerals are essential for plant growth, but not all rocks are the same. Igneous rocks from volcanoes like basalt have the highest mineral content. This means that they provide the biggest benefit for your soil.

It’s no coincidence that civilizations have been settling near volcanoes for thousands of years, as some of the most fertile soil in all the world can be found at the base of active volcanoes. These igneous rocks are full of beneficial minerals. Coming from the center of the earth, the minerals work well for aiding plant growth.

Volcanic activity pushes igneous rocks out of the earth and onto the surface where they are broken down by plant roots. Because these rocks haven’t been worn down or weathered on the surface before this point, their trace elements and micronutrients haven’t leached out. This means that powdered volcanic rock can be an ideal garden fertilizer. Once added to your soil, volcanic rock tends to break down faster than other forms of rock. With a higher quartz content, it makes more of it accessible to your garden plants more quickly.

Where is Volcanic Rock Dust Sourced From?

When a volcano explodes, it sends out rich layers of magma to the surface. After this magma cools and solidifies, it forms a type of igneous rock called basalt. This rock slowly breaks down on the surface and provides a steady supply of minerals to plant roots on the surface. Basalt is one of the most common rock minerals in soils around the world. Furthermore, it is an optimized way that nature works to pull nutrients from the center of the earth to the surface.

A Basalt Example: Mount St. Helens

When Washington’s Mount St. Helens erupted in 1980, it sent enormous plumes of volcanic ash and basalt into the atmosphere. At first, the ash-filled environment seemed unlikely to support life in any form. However, within a few years the beneficial effects of the basalt re-mineralization began to become evident.

The volcanic mountainside bloomed with a wider variety of plant life than had been present before. Then, within a few years the vibrant greenery made it difficult to tell that a catastrophic explosion had even occurred. The benefits of this injection of basalt in the region will aid plant life for decades. Obviously, leaving the area far healthier than it was before the blast.

How Does Volcanic Rock Dust Benefit Your Soil?

Understanding how volcanic rock dust works to help the soil is easy. Plant roots are voracious feeders that suck minerals out of the soil around them, and over time this depletes the soil’s natural reserves, causing plants to become stunted. By adding volcanic rock dust back to the soil, it makes it accessible to plant roots as soon as they make contact with it. As the rock continues to break down, additional nutrients are made available to the plant roots. Thus, guaranteeing them a consistent supply of nutrients.

Some supply stores classify volcanic rock dust as a fertilizer, but that’s not technically true. In fact, rocks like basalt don’t have quite the necessary levels of nitrogen, potassium and phosphorus (N-P-K) for it to qualify as a true fertilizer. Instead, the real benefit of volcanic rock dust comes from its mineral content and the trace elements like iron and manganese that are added back into the soil.

Plants given plenty of access to volcanic rock dust will grow bigger, faster and healthier than other plants. Their root structures will improve and strengthen, and they will have increased resistance to pests and diseases. Furthermore, they will have better flavor and greater nutritional value. The slow release properties of volcanic rock dust make it an easy way to minimize the deficiencies that fast growing plants experience, as it allows them to have a consistent feeding supply for longer than other forms of fertilizer.

Though scientists today are still researching the benefits of volcanic rock dust for crop health, it is proven that it works to improve root systems, increase plant yields and generally improve overall plant health.

Where To Buy Volcanic Rock Dust

Volcanic rock dust tends to be easy to buy at any organic garden center. Although, you can also purchase it online or from gravel pits. If you want to find a cheap, bulk supplier of volcanic rock dust, call your local sand and gravel suppliers to see where they source their supply from.

When you purchase volcanic rock dust, be sure to get particles that are as finely ground as possible. The closer the texture resembles flour, the better it is for your plants.

General Application Rates

Volcanic rock dust can make a big difference in small gardens, but it tends to be too expensive to be worthwhile in larger farms, unless you can find your own source. You can also put some directly on your lawn to make it more robust.

The general principle is to spread three tons of volcanic rock dust per acre, which comes to about 1.25 pounds per square yard. In the metric system, this comes to 750 grams per meter. Therefore, you should plan on about 10 to 15 pounds of rock dust being enough to re-mineralize a hundred square feet of garden space for up to three years. However, if you have a ready supply you can multiply these levels by up to eight times. This will help your garden to maintain the proper mineral levels for years to come.

To apply your rock dust, simply sprinkle it onto the top few inches of your garden bed and gently till it in. Make sure that it has contact with plant roots.




Additional Tips for Using Volcanic Rock Dust

Using volcanic rock dust in your garden is a simple process, but here are some additional tips that can help you find success.

  • Make sure to check your supplier for quality. Some companies misleadingly sell crushed concrete as rock dust instead of volcanic rock dust. Do your research to ensure you are really getting what you’re paying for!
  • Balance is important. It can be hard to get the proper levels of minerals into your soil if you don’t know what your levels currently are. Be sure to get a soil test before applying your basalt dust. That way you can see what your levels currently are and what you need to do to improve.