028-The Role of Minerals in Making Great Soil

| Care, Podcast

Now that the Thanksgiving week is behind us, I typically start to reflect on all the things that happened during the year that went well, and those things that, well, have room for improvement.

In the garden, it was a good year overall. But the wet, humid weather this summer wreaked havoc on my organic tomato crop and kept it from looking handsome and productive.  The truth is, despite the best possible growing conditions (and mine were pretty awesome), tomatoes don’t like excessive heat, combined with humidity and constantly wet foliage. It’s the proverbial recipe for disaster. And your tomatoes don’t mind letting you know it.


Healthy Garden with mineralized soil

Within weeks of adding my first application of mineralized soil, my garden seemed to jumped to life as I had never seen before. Coincidence? I think not.


That said, I have no other complaints. And there is nothing I could do about it anyway. So, I prefer to dwell on the successes, and what I did to help make them so. In fact, I opened my gardening timeline and went back five years. That’s the time I’ve been here at the GardenFarm with my raised bed garden and the native landscape beds and wildlife habitat I am developing over the five-acres I now call home.

Some of my Best Steps to Garden Success

  • Adding plenty of organic material. If you’ve heard me say it once, I’ve no doubt said it a thousand times. Or more. So, I’m not going to dwell on it here. If you want to know more about my love-affair with organic material and what it does to improve your garden soil, and therefore your entire garden, then simply type “organic” into the search field here and stand back. (Just be forewarned, allocate a few days to get through all the information).
  • Adding mulch. Again, if you still have time after reading how I feel about organic material, plan a few more days to read about my second love: mulch. It’s that good for the garden. If nature has the equivalent of what superfoods are for humans, organic material and mulch are that for our plants and soil.
  • Adding minerals to the soil. This is the one item that rarely gets mentioned that’s equally important. In fact, as soil amendments go, it’s the most important ingredient that no-one ever seems to talk much about. If you look at any typical soil model, it contains about 45% minerals (sand, silt, and clay), 50% air and water, and 5% organic material.


Piles of purchased soil about to go in the garden beds

My Georgia red clay is full of minerals. But it’s too dense to use in raised garden beds. Look closely, and you can see three large piles of purchased soil that will be blended to fill the beds.


So, if you’re paying attention, you’ve duly noted I spend a lot of time extolling the virtues of something in the soil that only comprises 5% of its total composition (and usually less).

Using that logic, why would I not spend exponentially more time talking about minerals that are more important and make up about 10-times more volume in soil?

Perhaps because talking about minerals (e.g., molybdenum, boron, and cobalt, etc.) is not as exciting as extolling the joys of taking vegetable scraps from the kitchen and garden debris and turning it into black gold—compost—nature’s miracle ingredient.

Why Mineralizing Soil is Important

Just like we need a balanced diet of vitamins “and” minerals, plants need that too. We need both, and so do they. And both work better when they have each other. While minerals don’t provide primary nutrients such as nitrogen, phosphorus, and potassium, minerals are essential elements plants need to function at their peak efficiency.

And if we don’t add minerals, either once depleted or absent, to begin with (as in beds filled with many purchased soil options), minerals missing from soil are minerals missing from the fruits and vegetables it produces.

As we all know, we are what we eat. So, if our plants don’t have minerals, how do we get them? By adding them to the soil through a process known as mineralization. It’s not anything complex.

In my garden beds, I purchased an organic garden soil blend that has topsoil, compost, and granite dust – a local mineral that contains calcium, potassium, sodium, and other beneficial trace elements.

A twice a year topdressing of about an inch and worked in lightly to the existing soil produced dramatic results in short order.

So how do you know what minerals to add and how much?

Get a Soil Test


Collecting a soil sample for testing

Collecting a soil sample for testing only takes a minute and should comprise a representative sample for the area where you will be growing your plants and crops


Unlike organic material that continues to break down quickly, minerals are a completely different story.

It’s much easier to add minerals to mineral deficient soil than to remove minerals from soil that already contains enough. And too much of a good thing is not a good thing. Plus, it’s not easy to bring mineral levels down quickly.

The key point in this message is that before you go randomly adding indigenous minerals to your garden soil, take the most important step first. Get a soil test that measures existing mineral levels. Only then will you know what you need to add and how much if any at all.

If you happen to know your soil pH level, soil with a lower than neutral pH (acidic) likely indicates mineral-deficient soil. Conversely, alkaline soil, where the pH level is higher than neutral (7.0) likely already has sufficient minerals. Arid climates are common areas where minerals may already be sufficient in native soils.

That said, purchased (imported soil) can be completely different. Even more reason for a soil test.


Soil Test Report

Cooperative Extension Soil Test Reports are a useful tool for basic information, including some minerals. If you want a more comprehensive report, including how to apply specific amendments to your garden, a private lab may be your best option.


Your local county Cooperative Extension Service is a common way to get a soil test analysis. For about $15, they will send you a report that provides the general makeup of your soil for nutrients and some primary minerals.

Private labs that you can find online will provide the same service for slightly more. Also, they will often provide additional information, especially related to minerals and most important, how to convert their data into usable information that you can apply to your specific garden crops and the actual size of your growing area.

To me, it’s worth the few extra dollars to have this service. While it’s helpful to know where you are starting with soil a nutrient and mineral analysis, what is most helpful is specific information that takes that data and applies it in a way that you can use that information in an applicable way.

Once you’ve added minerals to your soil per the suggested application rates, I recommend doing another soil test a year later. Because minerals don’t decompose quickly, combined with the importance of not over-mineralizing your soil, take the cautious route and re-test to compare the new results before you assume a need to add more minerals.

Go Forth and Mineralize

The bottom line is this. I pride myself in creating gardens worthy of wowing national television audiences. I’ve been doing so for over 15 years. But the most dramatic change I’ve ever noticed in such a short period was the season I first mineralized my soil.

While I cannot say with complete certainty that the cause of this dramatic change so quickly was the direct result of a single mineral application, I know of no other variable that came into play that season.

Plants jumped out of the ground with growth and vigor I’d never seen before. While I can’t promise, you’ll experience similar results, I encourage you to take the first step, by getting a soil test that measures mineral content. Then act accordingly. For many of you, I think you’ll raise the bar on your best garden ever.


Links & Resources:

Free Resource Guide: The Complete Guide to Home Composting

The Most Important Soil Amendment No One Ever Talks About

The Mineral Side of Soil – article from Humanity Development Library 2.0 – Peace Corp Information Collection and Exchange

The Intelligent Gardener; Growing Nutrient-Dense Food, by Steve Solomon (founder of Territorial Seed company) and Erica Reinheimer*. This is a good book that provides solid information on how minerals affect soil and its ability to contribute to healthy plants.

Logan Labs – The soil testing company mentioned in this podcast

Podcast: How to Improve Your Soil: 3 Simple Steps for Making Any Soil Better

Podcast: Composting A to Z: The Quick and Dirty on Everything Compost

How to Create a Productive Raised Bed Garden

Backyard Composting: A Simple Recipe for Making Great Compost

Milorganite: Our podcast episode sponsor and Brand Partner of joe gardener®

*Book link is an affiliate link

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

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