Remineralize Soil to Grow Nutrient Dense Crops

Ben and Penny Hewitt live with their two sons on a 40-acre homestead in Vermont, where they raise various livestock, including cattle, sheep, goats, and chickens, and grow vegetables and fruit.

Where does the family end and the homestead begin? The Nourishing Homestead (Chelsea Green Publishing, 2015) explores Ben and Penny Hewitt's small homestead in Vermont as they embrace a life nourished by good food, hard work, and loving family. They use "practiculture," a multitude of practical skills and philosophies from growing nutrient dense food to soil remediation, wildcrafting, and agroforestry, to build a thriving homestead. The following excerpt on bionutrient farming is from Chapter 5, "Soil and Gardens."

How biological activity changed everything

We came to our land in the northern Vermont dairy-farming community of Cabot in 1997. At the time, the cleared portions of our 40-acre piece of property were being grazed by a neighboring dairy farmer, in the let-the-cows-grub-it-down-till-there-ain't-nothing-left manner common to the industry. In other words, the pasture was receiving a severe beating on an annual basis.

That said, it could have been a lot worse. For starters, it was immediately apparent that we had a healthy layer of topsoil. And the land had not been plowed or tilled, or if it had, it had been so long ago that no visible evidence of these practices remained. Likewise, there was no indication that pesticides or herbicides had ever been sprayed. Finally, the soil drained extremely well.

All of this led us to believe that we didn't need to do a whole lot to grow vigorous crops. Like many home gardeners, we assumed that simply because we grew our own food, it would be as nutritious as food could possibly be. So we didn't do much. We hired a neighbor to till up a couple of garden plots, trucked in a few yards of compost, and started planting. We did get some basic soil tests analyzed by our local university ag extension service, and were quite pleased with ourselves when the results came back with everything in the "optimum" range. It was like being told our children were doing extremely well on their standardized tests.

Over the years, we began to observe that despite our so-called optimum soil test results, our crops sometimes lacked vigor and results were inconsistent. Sure, we were still producing lots of food, and we continued adding the amendments necessary to replace what our harvests took from the soil. But in truth, it felt as if we could be doing better. We were starting to get wise to the fact that growing our own did not necessarily mean optimal nutrition.

Now, just as this was beginning to occupy more of our mental energy (or in truth, more of Penny's mental energy; she's always been the green thumb around here), Penny happened upon a poster advertising a workshop with Dan Kittredge, founder of the Bionutrient Food Association in North Brookfield, Massachusetts. The BFA is a non-profit focused on teaching the importance of soil revitalization and the improved food quality that results, via the application of trace minerals and elements, seed inoculation, interplanting, and other techniques that foster biologically active soil and nutrient-dense crops. I should note that the BFA has begun using the term bionutrient food (hence the organization's name), rather than nutrient-dense food, since nutrient density is based on a different metric. But for the sake of clarity, and because nutrient dense is the term that brought us to this methodology, I'm sticking with it in this book.

Indeed, it was the phrase nutrient dense in the workshop poster that caught Penny's eye; for many years, we'd sought nutrient density in our diet, via traditional whole foods. The notion of incorporating nutrient density in our vegetable and fruit production efforts appealed to her immensely.

It is difficult to overstate just how profoundly that simple poster has impacted our relationship to the soil and, therefore, our food. After the first workshop she attended, Penny knew she'd found the missing link. "It's like I found something I didn't know I'd lost," she said when she returned home, where she danced a little jig in the kitchen, her eyes gleaming with excitement. When she finally calmed down, she launched into a partial list of all she'd learned, including (but by no means limited to):

  • Our habit of fertilizing our garden with compost we proudly made from vegetation and animal manure originating from plants grown in depleted soil only magnified soil imbalances, as the depleted compost was incorporated into the soil from which it came.
  • The role of insects and diseases in nature is to attack organisms that aren't fit for reproduction. Pests and disease are not the cause of crop failure, but rather symptoms of an already failing crop. With their simple digestive systems, larval forms of insects can digest only simple carbohydrates. If your plant cells comprise complex carbohydrates and complete proteins--as they do in healthy plants--they become inedible to these pests. Put simply, it's not food to them anymore.
  • As the soils' digestive system becomes stronger, plants begin storing excess energy in the form of fats (lipids). This helps them develop thicker, stronger cell membranes, and they become increasingly resistant to airborne pathogens like mildews and blights.
  • Eventually, plants can use higher levels of lipids to build essential oils, which serve as plant protectant compounds. Their immune systems become fully developed, and they are resistant even to insects with complex digestive systems like Colorado potato beetles (the scourge of practically every home grower we know), flea beetles, Japanese beetles, and so on. This is the point at which your food truly becomes medicine.

Penny's sense that she'd found something she didn't know she'd lost actually makes a lot of sense when the subject of soil health is placed in historical context. That's because the advent of modern agriculture, dependent on fertility derived from fossil fuels and gobs of chemicals (for instance, there are currently 1,200 active pesticide ingredients incorporated into 18,000 different products approved for use in the United States), is systematically destroying the biological activity of our soils. And as we lose this biological activity, we also lose minerals and nutrients, not merely in our soils, but also in our foods and our bodies. This is extremely bad for us, but like so many of the things that are bad for us, it's proven extremely profitable to the corporate entities presiding over the fundamental facets of our survival.

Furthermore, the contemporary view of soil health as being primarily about NPK and bushels per acre has overshadowed a much longer historical view of comprehensive soil health--articulated by soil pioneers like William Albrecht--that incorporates critical aspects such as trace minerals and biological activity. In short, it's not as if the recognition that these factors are critical to healthy soil is some radical new concept; it's just that the advent of for-profit, chemical agriculture has squashed these ideas beneath its too-big-to-fail fist.

The challenge with discussing soil remineralization and revitalization in general is that things get technical really quickly. Penny and I are not soil scientists. Nor are we chemists; in fact, neither of us remembers much, if any, of what we learned in our high school chemistry classes. But with the help of others, and some dogged persistence, we have learned an enormous amount and seen phenomenal results.

A thorough treatment of soil remineralization is beyond the scope of this book. Instead, please consider this a primer on the subject. Our journey toward truly optimal soil health and will provide you with the core information you need to begin your own journey in this direction. It is a journey that requires some effort and expense, but I can emphatically say that it will be well worth it, if you follow through. In fact, I strongly encourage you to find a workshop to attend; the Bionutrient Food Association leads workshops across the country and is in the process of establishing regional chapters. Remineralizing our soils has utterly transformed the vitality of our gardens and the food they produce, to the extent that we now consider investments in our soil to be the soundest investments we can make. That nagging sense of feeling like we could be doing better has been replaced by profound amazement at what our crops are capable of when grown in fully functioning soil.

Since we embarked on our remineralization campaign half a decade ago, we have seen marked increases in yields, to the point that we've actually decreased the amount of square footage devoted to many of our crops. We've also seen notable improvements in size and flavor. Our blueberries are larger, more deeply blue, and sweeter. Our garlic bulbs and onions have increased in size by 20 percent or more. Our cabbages, one of our most important crops because it serves as the foundation for kimchi and sauerkraut, two of our staple winter foods, are almost absurdly enormous and juicy. If this weren't enough to convince us we're on the right track, virtually everyone comments on the unique sweetness of our kimchi, most likely attributable to the high Brix of our vegetables. (Via the use of a refractometer, Brix is the best tool currently available for measuring the relative quality of crops. Put simply, Brix is a measure of sugars and minerals dissolved in water. The more sugars and minerals, the more nutritious the crop.) And everything stores much better; our root crops stay crisp and flavorful for longer than we'd become accustomed to.

What's more, the prevalence of insects and disease in our gardens is greatly reduced. Every so often, we still find a handful of Colorado potato beetles, which we relish ushering to the pearly gates with a quick pinch of thumb and forefinger. But it's nothing like the hours upon hours we used to spend each summer trying desperately to stay ahead of those little ravaging monsters. If we could have back all the hours we spent hunched over our potato plants, squishing and smearing, there's no telling what we could accomplish (in fact, just a few days before I wrote this paragraph, my son Fin commented that he couldn't remember what a Colorado potato beetle even looks like). And in recent years, when late blight has decimated neighboring tomato crops, our tomatoes have been more prolific than ever.

At first, we assumed this was all a fluke--after all, most crops vary from season to season--but after the third consecutive year of improvement, it dawned on us that we'd reached a new normal. Indeed, five years after Penny went to that first workshop, our harvests are still improving. It seems as if every season, we reach a newer normal that is even better than the last.

Shifting Your Perspective on Soil

The first key to understanding why your soil needs a balanced complement of minerals involves a simple shift of perspective. Instead of merely thinking of soil as the medium in which plants grow, think of it as a living, breathing entity. The soil is your gardens' heart, lungs, and nervous system. It is the immune system for your plants, as critical to the health and vitality of your fruits and vegetables as your immune system is to your health and vitality. If your soil is not fully healthy, your crops will not be fully healthy. If your crops are not fully healthy, you will not be fully healthy. In a sense, you eat the soil with every bite you take, and it cannot be overstated just how important it is to ensure that your soil functions as optimally as possible.

The second key to understanding soil remineralization is explained by the weak link principle. In short, your crops' capacity to achieve their full genetic potential will always be limited by whatever critical mineral is most deficient. This is one reason why, despite our early soil tests showing optimal levels of macronutrients and organic matter, our fruits and vegetables were not achieving their full potential.

Like commercial farmers, most home gardeners focus on the macronutrients of nitrogen (N), phosphorus (P), and potassium (K), as well as organic matter. It's not that these nutrients, along with sufficient organic matter, are not important; it's just that they tell only part of the story. Now that we better understand the role of trace minerals and elements, we amend for NPK as well as sulfur, calcium, and magnesium, along with boron, manganese, copper, zinc, cobalt, molybdenum, and selenium. The irony of amending only for NPK is that while it produces a noticeable short-term boost, over the long term, it actually suppresses the microbial communities in the soil, which ultimately creates less healthy soils and decreases the vigor of plants. At which point, the enterprising grower applies more NPK and the cycle begins all over again. When you bring minerals into balance, the entire soil ecology and all the microlife comes into healthy balance, also.

Obviously, all this amending does not make our lives less complicated, and it is certainly not free. And the process has compelled us to buy in amendments and mined minerals from far off our farm, in contradiction to many of our stated goals. We have chosen to do so in light of the fact that we have young children now and wish for them (and ourselves) to be eating the most nourishing food we can produce. There are local materials (such as rock dust and manure teas) that can supply many of these minerals, but they will take a much longer time. In regard to the finances, we have simply prioritized our soil. To us, any money spent on soil is an investment that returns good health to the land and to us. Therefore, anytime we have extra money, we generally seek ways to invest it into our soil.

It is also worth pointing out that once our soils are fully rebalanced and restored, we will no longer need to amend as diligently as we do now. Of course, we'll continue to test our soil regularly and make whatever adjustments are necessary, but as our soils become more balanced, the need for inputs should decline to merely replacing what we take on a year-to-year basis, rather than compensating for decades of mismanagement and natural erosion. But because a highly mineralized and balanced soil makes a great deal of organic matter on its own, only modest applications of compost should be necessary. And the fact that our compost now consists of healthy ingredients means that it no longer exacerbates existing imbalances.

How to Achieve Optimal Soil Health

The first step toward achieving optimal soil health is obtaining a complete soil test, using the instructions provided by the testing lab. But do not assume that your local university ag extension soil test measures these values! We've been very happy with the tests we've gotten from Logan Labs in Lakeview, Ohio, although there are probably other labs capable of providing complete test results. However, the Bionutrient Food Association website includes a downloadable soil test form that is specific to Logan Labs and ensures you'll get comprehensive results. Note that because different labs analyze soil differently, the desired values that follow apply only to Logan Labs.

We gather soil samples in fall, in accordance with the instructions on Logan Labs' website. This allows us enough time before freeze-up and snowfall to calculate our amendments and then to actually spread them, so they have ample time to work their way into the soil and mellow before spring planting. In the case of water-soluble amendments, we wait until spring to apply.

A word on gathering samples. As you'll see in the instructions to follow, there are numerous ways to go about getting the soil samples from the ground. Our favorite method is to collect core samples with a hollow soil sampling tube (see second image in the slideshow). The readily available, mass-produced models tend to be lightweight, and over the years, we've mangled several beyond recognition. Last year, we hired a local blacksmith to make one to our specifications, and simply from its heft and overall quality, I'm confident we now have a lifetime soil sampling tool.

Interpreting your soil test is where things get a bit complicated. The values on your test represent what is available in the soil to feed your crops; that much is fairly straightforward. Once you know these values, you can begin the process of applying this knowledge to your particular situation. The first step is knowing what those values should be, which is somewhat complicated by the fact that different people have different ideas regarding what constitutes the ideal soil. (We use values provided by the Bionutrient Food Association, which have obviously worked extremely well for us. It's critically important to note that soil health is not about having more and more of particular values, but about having the proper balance.

With your actual current values and ideal values in hand, you'll need to call up a bit of high-school-level science and math to move forward. This has been a challenge for Penny and me, as neither of us was a particularly ambitious student, and this is one regard where I can confidently, without a shred of doubt, say that if a couple of formerly underachieving high school students can do it, you can do it. The truth is, I suspect most people will need a little help the first time they attempt to translate their soil test into a recipe for proper amending, and I encourage you to seek out a workshop or soil expert in your region.

This is how we do it. First, we subtract the value found of a given substance from the desired value, to arrive at the quantity we need to amend for. The values on the test results we get are expressed in parts per million (ppm), but we need to know pounds per acre (ppa) to determine application rate. This sounds confusing, but by multiplying ppm by a factor of 2, it's actually quite easily attained. This works because the top 6 inches of soil, which is the depth of soil that has been tested, equates to 2 million pounds per acre.

We're not quite done with the math. Since most home growers aren't dealing in acres of crops, we need to convert pounds per acre to pounds per square feet, which is as simple as multiplying ppa by the square footage of the area you're amending and dividing by 43,560, the number of square feet to an acre.

Now that we have the pounds per square foot that we need to supply of each deficient element, we need to determine how to get that amount from the variety of amendments at our disposal, some of which contain two or more elements. Keep in mind that the elements are merely a percentage of the amendment; for instance, gypsum is 23 percent calcium and 19 percent sulfur, so each 50-pound bag of gypsum has only 11.5 pounds of calcium (50 pounds x 0.23 = 11.5 pounds) and 9.5 pounds of sulfur (50 pounds x 0.19 = 9.5). Many of the micronutrients will be expressed in grams and ounces, not pounds, so you'll need a kitchen scale capable of weighing very small amounts. Also keep in mind that there is a maximum annual application rate for many of these amendments. This is critical, because some of these traces can be toxic in large quantities. In some cases, it may take multiple years to achieve desired values while not exceeding maximum annual application rates.

Once we have our amendments for a given area figured out, we mix them in a wheelbarrow (remember to always wear a dust mask and gloves!) with a source of carbon in the form of biochar, compost, or humates. The purpose of these carbon sources is to give the amendments something to bond to, making them less likely to leach out of the soil. Finally, we spread our amendment-and-carbon mix as evenly as possible, scooping from the wheelbarrow with a 1-quart yogurt container. Since we don't till, we allow the rain and snow to water them in for us.

Once you've got your soil on the road to recovery, there are other ways to improve your plants' potential. In fact, some of simplest and most cost-effective steps along the path to nutrient-dense crops begin before the first shoots of green begin to emerge from the soil.

This article is adapted from Ben Hewitt's The Nourishing Homestead and is printed with permission from Chelsea Green Publishing. You can buy this book from the GRIT store: The Nourishing Homestead: One Back-to-the-Land Family’s Plan for Cultivating Soil, Skills, and Spirit.

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Ben Hewitt
February 2015