Show Transcript
0:00Hi guys, Jonathan here with Farmers Friend and I'm at Bountiful Blessings Farm with my dad John. We're reviewing some questions that some of our customers have submitted and we have a
0:09question from Trina. She says, "We've gotten soil tests done last fall and would love to know how to read them. Do we need a soil professional NRCS? Not
0:18sure who to use as a resource or maybe you have some tips. We know every soil is different, of course. Thanks. Looking forward to this weekly Q&A.
0:27So, soil soil science, it's a it's a big deep broad topic with lots of different opinions and perspectives.
0:37People get PhDs in this, you know. Yeah, exactly.
0:41There's a lot of different opinions, but let's how about this? Let's just, you know, may maybe touch on it from a high
0:47level, but probably most helpful would be just to hear how you guys have handled it and what your approach is to managing soil health.
0:56Yeah. Well, even that would be a long answer, but um you know, she says, "We'd
1:03love to know how to read them." Uh, you know, my my advice would be for starting
1:10out just working with a professional who knows how to read them because it is it is a science. Although, it's
1:18interesting. Elliot Coleman um in his new organic grower book, he says um soil testing is part science and
1:28part necromancy. Yeah. And I thought that was interesting. In in other
1:35words, it's not maybe as true a science as people would like it to be. There are
1:42a lot of questions and a lot of variables. So yeah, I would encourage starting out by using a professional.
1:50Ideally, somebody who knows your part of the country well, knows what the soils are like there. Do you think uh aggra
1:59extension is a good place to go for that or um you know, do we have any resources you could recommend there? I mean, I
2:08think that varies a lot from stateto state. Yeah. You know, I think there's more a extensions that are are learning
2:17about organic agriculture, but traditionally I found the a extension is not real helpful for organic solutions.
2:27Yeah. Um so you could give it a try and and see if you're from a progressive state that's really up on that. Um yeah.
2:38Yeah. A lot of times the a extensions are just going to be, you know, able to help with like, I don't know, livestock
2:45related stuff and like rowcropping and those types of resources. But yeah, when it comes to diversified veh, you know,
2:51organic vegetable production, that's not generally their wheelhouse. Yeah, I would say that's a pretty accurate
2:58description from my experience, but I I do know some states that are pretty progressive with it, which is good.
3:05Yeah. Um, I wanted to just show some books. You know, I came from the generation that actually read books. So,
3:14I don't know how old you are, Trina, but um there's three books I've got here
3:20which I think are very good as as just a kind of basic overview of soil science. The
3:29Intelligent Gardener by Steve Solomon is an excellent book.
3:35Um, the soul of soil by Joe Miley and Grace
3:42Gershuni. Um, and then there's soil science for gardeners. Um, working with nature to build soil health by Robert
3:51Pavas. So those are a good place to start to give you kind of a broad foundation and um, you know, if you want
4:00to go deep into it, you can certainly do that. There's lots of other books and resources.
4:07Um, but currently my favorite uh soil expert, I guess you would say, is
4:16John Kemp because I I love his kind of holistic view of things. And I recently
4:23watched a webinar of his called soil testing 2.0. and he kind of uh brought the whole
4:33idea of soil testing into question from his research and his uh work in the
4:41field. He said that many times the results of the soil test do
4:48not correlate to what they find in sap analysis, which is what they do a lot
4:54of. In other words, it may or may not be in the soil, but even if it is in the soil, it doesn't mean it's going to get
5:02in the plant because it's very uh intricate and complicated how how
5:11minerals get from the soil to into the plant and and of course the biology is a huge part of that.
5:21So, you know, his his point and and I did want to just point this out and I would encourage you to watch this this
5:29webinar if you have a chance, soil testing 2.0. But he said the calcium to
5:36magnesium ratio, boron, sulfur, and zinc, those four things seem to correlate pretty well. In other words,
5:45soil tests seem to be pretty accurate in reporting those, you know, what what
5:52ends up in the plant. But all the other things, you know, and that includes your your big ones, your macronutrients,
6:00nitrogen, phosphorus, and potassium, there's not a a direct correlation between what this shows up
6:08on the soil test and what shows up in the plant. Interesting. So, just to make it a little more complicated and
6:16confusing, but but so John Kemp, he has a consultation service or like you can send your results to them and they'll
6:24give you advice on on your, you know, fertilization program,
6:30right? Well, he he they don't do a lot of soil testing. they they focus on the
6:37sap analysis, but but again that's more for big growers because it's quite expensive to do. Um for the little guys
6:46like us, he just has some general protocols of materials that he either
6:54sprays on the soil or sprays on the plants that we found very helpful. Yeah.
7:00Well, I mean I feel like the results speak for themselves. So if you've been getting good results, then that's yeah,
7:09that's what matters, right? So cool. All righty. Well, Trina, you've you've got uh three books to read to give you a
7:16basic understanding of soil science here. So, uh you know, it's it's a it's a deep topic and you're not going to,
7:25you know, become a professional in, you know, your first or your second or your fifth year. Uh but or your 25th year.
7:32Yeah. But, you know, just uh you just got to keep diving in and trying things and and figuring out what works for you.
7:39Digging in, I think, is more appropriate. Sure. Uh dig in. Anybody watching, if you have other questions that you would like us to review, click
7:48that link down below and submit them and maybe we'll add that to a future conversation. Until next time, happy growing.
How to Understand Soil Testing on Your Market Farm
By Jonathan Dysinger and John Dysinger
Updated on
Soil testing is valuable but more complicated than most beginners realize — it's part science, part interpretation. Start by working with a professional who knows your region's soils, read foundational books like The Intelligent Gardener by Steve Solomon, and understand that standard soil tests don't always correlate to what's actually available to your plants. Focus on what the tests do report reliably — calcium-to-magnesium ratio, boron, sulfur, and zinc — and build your soil health program around good biology, not just mineral numbers.
Soil testing is one of those topics where the more you learn, the more you realize how much you don't know. People get PhDs in soil science, and even then, there's plenty of disagreement about what the numbers on a soil test actually mean for your crops.
A customer named Trina recently asked us: "We've gotten soil tests done and would love to know how to read them. Do we need a soil professional? Not sure who to use as a resource."
My dad, John Dysinger, has been managing soil health at Bountiful Blessings Farm for 27 years. His answer to this question is honest and practical — and it might surprise you.
What Is a Soil Test and What Does It Actually Tell You?
A soil test measures the mineral content and chemical properties of your soil — things like pH, nitrogen, phosphorus, potassium, calcium, magnesium, and various micronutrients. Most soil tests are done by sending a sample to a lab, which returns a report with numbers and sometimes recommendations for amendments.
Here's the part that catches a lot of people off guard: those numbers don't always tell you what's actually getting into your plants.
My dad recently watched a webinar called "Soil Testing 2.0" by John Kempf — one of his favorite soil health experts — and it challenged the conventional thinking about soil testing in a significant way. Kempf's research found that standard soil test results often do not correlate with what shows up in plant sap analysis (a more direct measurement of what nutrients the plant is actually absorbing).
The reason is that the journey from mineral-in-the-soil to mineral-in-the-plant is incredibly complex. Soil biology plays a huge role in making nutrients available to roots, and that biological layer isn't captured by a standard chemical soil test. A mineral can be present in the soil but completely unavailable to the plant — or the test can miss nutrients that biology is actively delivering.
As Eliot Coleman puts it in The New Organic Grower, soil testing is "part science and part necromancy." It's a useful tool, but it's not the precise, definitive answer many beginning growers assume it is.
Which Soil Test Results Are Most Reliable?
According to Kempf's research, there are four things that standard soil tests do report fairly accurately — meaning the test results correlate well with what actually ends up in the plant:
Calcium-to-magnesium ratio, boron, sulfur, and zinc.
These four seem to translate reliably from soil test to plant uptake. The major macronutrients — nitrogen, phosphorus, and potassium — don't show the same reliable correlation. That doesn't mean NPK testing is useless, but it does mean you shouldn't assume that a high phosphorus reading on your soil test means your plants are getting plenty of phosphorus.
This is why my dad has increasingly focused on building healthy soil biology rather than chasing specific mineral numbers. If your soil biology is strong, it does much of the work of making nutrients available to plants — work that no amount of targeted amendments can replace if the biology isn't there.
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How Should a Beginning Farmer Approach Soil Testing?
My dad's practical advice: start by working with a professional who knows how to read the results.
Interpreting a soil test requires context — what's normal for your region, your soil type, your crops, and your management history. A raw lab report with a bunch of numbers isn't helpful if you don't know what to do with them.
Finding the Right Professional
The natural starting point is your local agricultural extension service, but my dad's experience — and this varies state to state — is that extension services aren't always well-equipped for organic vegetable production. They're typically strongest in livestock, commodity crops, and conventional row farming. Some states are more progressive about organic agriculture than others, so it's worth checking what your local extension offers.
Beyond extension, look for soil consultants or agronomists who specialize in organic or regenerative agriculture in your region. Someone who knows your area's soils and has worked with diversified vegetable operations will give you much more relevant guidance than a generalist.
Educate Yourself Over Time
You don't need to become a soil scientist to run a profitable farm. But building a basic understanding of soil health will help you make better decisions year after year. My dad recommends three books as a solid foundation:
The Intelligent Gardener by Steve Solomon — An excellent overview that connects soil testing to practical growing decisions. My dad considers this the best starting point for understanding how soil minerals affect crop health and quality.
The Soul of Soil by Joe Smillie and Grace Gershuny — A broader look at soil health from an organic perspective, covering biology, chemistry, and management practices.
Soil Science for Gardeners by Robert Pavlis — A science-based but accessible introduction to how soil actually works and how to work with nature to build soil health.
These three books will give you a broad foundation. You can go as deep as you want from there, but even reading one of them will change how you think about your soil.
Follow John Kempf for a Modern Perspective
If you want to go deeper into the cutting edge of soil and plant health science, my dad's current favorite resource is John Kempf — founder of Advancing Eco Agriculture. Kempf takes a holistic approach to plant nutrition that goes beyond traditional soil testing, incorporating sap analysis and foliar feeding programs.
His "Soil Testing 2.0" webinar is worth watching if you want to understand why conventional soil testing has limitations and what emerging approaches look like. Sap analysis — testing the actual plant tissue to see what nutrients are present — is more expensive and generally used by larger operations, but Kempf also offers general protocols for foliar sprays and soil applications that smaller farms like Bountiful Blessings Farm have found very helpful.
Frequently Asked Questions
Start by working with a professional — an agronomist or soil consultant familiar with organic vegetable production in your region. Raw soil test numbers require context to interpret properly. Focus on the metrics that reliably correlate to plant uptake: calcium-to-magnesium ratio, boron, sulfur, and zinc. For macronutrients like NPK, understand that soil levels don't always reflect what's available to your plants.
Soil tests accurately measure what minerals are present in the soil, but that doesn't always correlate to what your plants can actually access. Soil biology plays a critical role in making nutrients available to roots, and standard chemical tests don't capture that biological activity. Think of soil testing as a useful but incomplete picture.
It depends on your state. Some extension services are progressive about organic and diversified vegetable production. Others are primarily geared toward livestock, conventional row crops, and commodity agriculture. It's worth checking what your local extension offers, but for organic market farming specifically, you may need to find a consultant who specializes in that area.
Three recommended starting points: The Intelligent Gardener by Steve Solomon (connects soil testing to practical growing), The Soul of Soil by Joe Smillie and Grace Gershuny (organic soil health overview), and Soil Science for Gardeners by Robert Pavlis (accessible science-based introduction). For a more advanced and modern perspective, follow the work of John Kempf at Advancing Eco Agriculture.
Sap analysis tests the actual plant tissue to determine what nutrients the plant is absorbing — a more direct measurement than soil testing. It's more expensive and typically used by larger operations. For small-scale market farms, general foliar spray protocols (like those recommended by John Kempf) can provide similar benefits at a more accessible price point.
The calcium-to-magnesium ratio is one of the soil test metrics that reliably correlates to what your plants actually uptake. An imbalanced ratio can affect soil structure (too much magnesium tightens soil, too much calcium loosens it) and plant health. It's one of the first things to look at on a soil test because the numbers tend to mean what they say.
Yes — but with realistic expectations. A baseline soil test gives you a starting point and can identify major deficiencies or imbalances. Just don't expect the test to give you a precise recipe for perfect soil. Combine testing with good organic practices — compost, cover crops, crop rotation — and build your understanding over time.
The Takeaway
Soil testing is a useful tool, but it's not the crystal ball many beginners expect it to be. The numbers on a soil test report are a starting point for conversation, not a definitive prescription.
Start by working with a professional who can interpret your results in the context of your region and your growing system. Build your own understanding over time through books and resources. Focus on soil biology as the foundation of plant nutrition — not just chasing mineral numbers. And pay attention to the metrics that actually correlate to plant uptake: calcium-to-magnesium ratio, boron, sulfur, and zinc.
As my dad says, you're not going to become a soil science professional in your first year, your fifth year, or even your twenty-fifth year. But you'll keep getting better at it — and your soil will keep getting better with you.