Orchard People

#067 Soil and Tissue Testing with Jack Legg
[00:00:00] Introduction to Soil and Its Mysteries
Susan: Soil is such a mystery. On the one hand, it looks pretty similar wherever you go. There are differences, though. Sometimes soil is dark brown. Sometimes it's lighter brown. Sometimes it can look a bit orange or a bit red, but what we really want to know is how fertile our soil is, and how well it can support our plants and trees.
Is it rich in nutrients that can support plant life? Are those nutrients accessible to the plants that we are growing?
[00:00:34] Signs of Soil Fertility and Plant Health
Susan: Now, you can get a clue by looking at the health of your fruit trees and other plants. Are they growing vigorously? Do their leaves look healthy? Are they producing healthy looking fruit?
Those are all very good signs. But, if there is something wrong, maybe your fruit trees seem overly vulnerable to disease problems. Maybe the harvest quality isn't too good. It might not actually be your fault. Your soil may not be well suited to the plants that you're growing. It may not have enough of the nutrients that your plants need.
[00:01:10] Importance of Soil Testing
Susan: And so in today's show, we're going to talk about soil testing for fruit trees and other crops. We'll learn how labs test soil and what they're actually looking for. We will also discuss home soil testing kits. Do they work? Are they worth the money?
[00:01:27] Meet the Expert: Jack Legg
Susan: And so my guest on the show today is Jack Legg, an agronomist from SGS Canada, which has been providing services to the agricultural industry for over 70 years.
Jack is passionate about soil testing, and he's great at communicating even the trickiest scientific concepts about soil. So I'm really happy to have him on the show.
Jack, welcome to the show today.
Jack: Thank you, Susan. Glad to be here. And I'll add to that intro. I'm not just a soil expert, but I also have fruit trees in my own backyard so, like you, I'm very passionate about growing fruit.
Susan: Wonderful. What kind of trees do you have in your backyard?
Jack: We have cherry trees, pear, apricot, plum, and apple.
Susan: Wonderful. Then let's start there. Why do we need soil testing? Could we just look at our plants and trees? Don't they tell us, with the state of their health, what nutrients they need?
Like maybe there's one problem with the leaves that indicates a lack of nitrogen or phosphorus or potassium. Do we really need soil testing?
Jack: Of course, visual symptomology is often very revealing in what might be deficient in a plant or a tree specifically. However, if you are witnessing visual symptoms, you're at the point where there's probably been a hunger in that plant for some time, likely yield reduction. And just like us, when we're missing nutrition, it makes us more susceptible to getting sick. So same with the trees.
Now, soil testing is a good way of taking a snapshot of what your fertility is. Soil testing is a good indicator of your relative nutrient levels.
However, what it doesn't do is predict how well your plant or tree will utilize those nutrients. So if we have time later, maybe we'll touch on tissue testing, because tissue analysis is a good indication of how well those nutrients are being utilized, whereas a soil test is an indication of how much that soil has the capability of providing to the plant.
Susan: Perfect. And yes, I do wanna talk about tissue testing. We will talk about that in the second part of the show. So essentially, you're saying that our soil test is going to reveal the secrets of the soil in terms of what nutrients are actually in there. But my question is, how do you take some soil to a lab, and how can it tell us this?
Like what is the secret?
Jack: Yes, and that's the trick with soil testing because most testing across the world for most things is quite universal. The same method is used for the same test wherever you happen to be. However, with soil, as we know, it's quite variable from region to region. Susan and I are Ontario.
We have fairly young soils, glaciation, not very deep, only about six inches, and they tend to be high in calcium, high in magnesium and high pH. They're calcareous soils, having been derived from limestone parent rock material. So because of the variability of soil from one region to the next, and climatic conditions as well, we have winters. Many locales don't. There are different methods that are accredited locally to best represent the amount of nutrient that the plant can find available in that soil. So because pH is about the biggest influence on how soluble or how plant-available nutrients are, we have methods that are approved to best determine how much of that nutrient can be pulled outta the soil for the plant.
[00:05:10] Understanding Soil pH and Nutrient Availability
Susan: Okay, so let's start with pH. pH seems to be the entry point for soil testing because your soil can have lots of nutrients in it, but if the pH is wrong, your plants won't be able to get those nutrients. I like to say when I teach classes on soil, that it's like being at an all you can eat buffet with lots of food and your hands tied behind your back.
You can't really get all those nutrients and that's. Isn't that essentially what happens if your pH is wrong? It doesn't really matter what nutrients are in the soil, you maybe can't get them, or the plant can't get them. Is that true?
Jack: Yeah. So that's what happens, Susan. At low pH, so say less than 6.0, some of the other elements in the soil like iron and aluminum were very happily combined with a plant nutrient like phosphorus, and they'll make these stable compounds that don't readily dissolve and the plant can't take it up. The same thing at the high end of the pH scale when you get alkaline. So say when you get above 7.5, which isn't uncommon in Ontario and many of the great Lakes basin soils, that when you're at high pH that same element, phosphorus of plant food will very happily combine with calcium.
Because it is less soluble, it's less efficient in being taken up by the plant. Now, that's not to say, that below six or above seven and a half that all of a sudden, no nutrients are available. They still are, but it's a reduced efficiency. So maintaining soil pH is important. It's much easier to raise pH with an addition of limestone than it is to lower pH with sulfur.
It can be done, but it's very slow and inefficient.
Susan: Okay. So pH is the entry point and that's one of the first things that we find out from our soil test. So once we get that in place, we find out the pH, and then we're testing for the major nutrients, the macronutrients that our plants need.
[00:07:07] Soil Testing Procedures in the Lab
Susan: How is it that a lab, like your lab, like the University of Guelph lab, and there's labs across North America. What do they do with the soil that we send in our sample box or in our sample bag? We get some soil from our garden. We take samples, we mix them together. We give a composite sample to you of our soil.
What do you guys do with it then?
Jack: The first thing we do is we dry the sample down. Now, we are limited to drying temperature to 35 Celsius because if you dry much hotter than that, then the clay particles will start to lock up the positively charged cations in the soil. The potassium, calcium, magnesium.
So we dry it at a temperature 35. We call it an oven, but it's essentially a hot room with no humidity. We dry the sample down, we grind it, which helps to homogenize the sample. And then from that, we take a small portion and we add an extractant.
So in the case of phosphorus, we're adding sodium bicarbonate, which is the extractant that has been shown in Ontario to dissolve a similar amount of phosphorus that the plants could find in the soil. So what we're trying to do is duplicate the availability of that nutrient in the test for potassium, it happens to be ammonium acetate.
So we use these chemical extractions because they've been shown to be the best representation of plant-available nutrient. Really what we're testing, though, is the ability of the soil to provide that nutrient to the soil solution. So it's not really an absolute measurement. It's more of an indication of a low test would suggest a poor ability to supply that nutrient.
Therefore, the crop would be enhanced by adding more of that nutrient.
Susan: It's interesting, Jack. You once said to me that we're not measuring the amount of nutrients in the soil. We're not. We're measuring the amount of plant-available nutrients in the soil. How much of the nutrients are available to your plants.
Is that correct?
Jack: That's right. And it could be a very small percentage. In a mineral soil, which is essentially sand, silt, and clay particles, much of that plant nutrient, potassium, for example. It is tied up in the very small particles of rock. It might take hundreds to thousands of years of weathering for that to release, to be able to be dissolved and taken up by the plant.
So some naysayers might say, we're not measuring the total amount, so why bother? Really it is only that portion that the plant can take up. That's important. An example I've used is, if you were to put a hundred dollars in the bank today, you could take a hundred dollars out tomorrow. But in soil, if you have a hundred pounds, let's say of nutrient in the soil, you might be only able to take out one pound per day.
So it's only that amount that we can find available, as we say, that we're interested in measuring. And then also keep in mind that the soil test is just the first step. Maybe I'm getting ahead of myself, but the second step is coming up with a recommendation. And that is compared to field trials, so that we know that a test at a certain level for a certain nutrient has what likelihood of response by adding more as compared to field trials, which were also done locally.
Susan: So we'll talk about that in a minute.
[00:10:34] Listener Questions and Expert Answers: The Importance of Looking at the Bigger Picture
Susan: We've got a couple of emails here.
Jack: Great.
Susan: First one is from Jennifer from Manhattan, New York City. Hello, Susan and Jack.
Very interesting topic today. No questions as of right now, but I just wanted to say hello from Manhattan. Love your shows and podcast. Thank you very much, Jennifer. And we've got a question here. Okay, so this question is from Irene in Burlington, Ontario. Hello. When you talk about soil testing and nutrients in soil, what's the most important thing to consider out of everything that may go wrong, or maybe good, when considering how to grow things?
So the most important thing to consider that may go wrong or the most wonderful thing that you could find out from your soil test?
Jack: That's an easy question with a more difficult answer. So really, although we talk about macronutrients and micronutrients or some may say primary and secondary, not one is more important than the other.
They're just used in different quantities. It just happens that plants use nitrogen, phosphorous, potassium in greater quantities than some of the other nutrients like zinc and manganese. I should also point out that, although we're talking about chemical testing today, the nutrient fertility of the soil, that's only one part of the bigger picture. The physical structure is important.
So that includes the particle size, the texture, the organic matter, how well that soil holds together or resists compaction, allows water infiltration and air infiltration, and there's also the whole biological component. All those good bacteria, fungi, microorganisms that all play a role.
Easy question. What's the one thing that could go wrong? But really, you need the confluence of all these good things, physical, biological, chemical, with a little luck and a little bit of help from mother nature and sometimes a bit of magic. And it all comes together to work.
Susan: That makes total sense. It's essentially this amazing jigsaw puzzle and you wanna get all the pieces in place.
With regards to that question, you can have everything looking good, lots of nutrients, lots of structure, but whoops, the pH is really wrong. That sets the whole thing off. So it's getting the perfect balance. And the great thing is that we are empowered to do that with recommendations from the lab, or wherever we send our soil sample to. Soil can be improved.
Is that correct?
Jack: Yeah, that's true. And it's also important to realize that a fertile soil is not necessarily productive, because if you have all the nutrients you need, but the soil is heavy clay and compacted very tightly, and the roots can't penetrate and the water runs off, then that's a good example of showing how the physical plays a role in it as well.
On the opposite end of it, you could have soil that's very deep and rich and full of organic matter, easy for the roots to penetrate. You might not need high fertility because the roots can find all the nutrients they need. And on the other end, we can have soils that are too good, some nice black, rich compost.
If we add too much of that, it can overwhelm the system. It can be so rich that it's salty. An example I use sometimes is that it'd be like taking a whole bottle of vitamins every morning instead of just one. Too much of a good thing is too much. So we need the proper balance of everything for it to work.
Susan: That was a great question and that's a great answer.
[00:14:20] Nutrient Dynamics in Soil and Plants
Susan: We have a question here from Julie, a regular listener from Ontario. Julie writes, hi Susan. Always love listening to your show. Wondering if you can go over how the nutrient contents within the leaves change naturally in a healthy tree from spring through fall.
And do you have any good resources on how these changes differ among the different fruit trees? So we'll talk a little more about this after, but do you have any comments on how the nutrients change within the plant?
Jack: Yeah. Also another great question.
To know where you would want the optimal concentrations of all the nutrients to be on all the species, you would have to test every plant every week through the growing season, and then compare that to something to know whether it's good or bad.
So some of that work has been done. People have looked at that.
But the difficulty also is having a timing standpoint for comparability purposes. So we might say 10 weeks after dormancy, as a time point, right? But every year that might be a little different. And if you were to take those tissue samples after a week of hot sunshine, droughty conditions, it would probably be different after a week of cool and moist and good growing conditions.
So yes, it would be great to know the uptake of every nutrient for every week of the growing season. Very difficult to manage. And even if we had those perfect ratios, I'm not sure how you would be able to manage that in such a way that you'd be spoon feeding the nutrients to the plants as well.
Susan: Yeah, I see what Julie is saying. And, what you're saying is if we know that my plant needs a lot of nitrogen in the spring, but then in the fall or in the summer, it needs more potassium, it would make fertilizing a little bit easier.
Jack: That's true.
And, we do know that certain things, as you mentioned, like more nitrogen in the spring when the plant's coming outta dormancy, and it's got that rapid vegetative growth, it's looking for things like nitrogen.
When you're flowering, any stress on the plant, so flowering, fruiting, filling out the fruit, all these different parts of the physiological age of the plant through the growing season, we'll have different needs nutritionally.
But what we say from a soil fertility standpoint is we'd like to have everything non-limiting, meaning there's more than enough there, so you're not going to run short.
Susan: And I guess that's the thing. Making sure the buffet table is full, so making sure the soil has everything and the plant will know what to take in when it needs it. True?
Jack: Yeah, that's right. Yeah.
Susan: Interesting. Okay, we've got another email here. This one is from Daryl in British Columbia. If a gardener adds a soil amendment like sea soil, how long would it take the nutrients to reach the roots of an apple tree? Also, what are some companies that test soil for gardeners in British Columbia?
So I don't know what this sea soil amendment is. Maybe you do, Jack, but I think it's a fantastic question. When you add an amendment, how long does it take to get to the roots?
Jack: Yeah. it's going to depend on the amendment, on the addition that you're putting on. Now obviously, the difference with a permanent crop like fruit trees and a vegetable crop, is that you're very limited in the way you can work that nutrient into the soil. We're not rototilling around fruit trees, for example. So most of it's surface applied. Aerating the soil would help, who would help get things down below the surface. It also depends on how soluble that nutrient is. So if it can dissolve in water, it'll quite readily go down into the soil and be held tightly there by the soil particles and accessible by the roots.
If it's something that's slow to dissolve. So an example I sometimes get approached with is rock phosphate, an organic source of phosphorus. It has phosphorus content in it, but it's very slow to dissolve and release that. So some things might be as quick as a day after a good rainfall, if they're very soluble.
Some things might be weeks and weeks.
Susan: And I've just looked up this interesting supplement. It's called Original SEA SOIL. It's a fully composted mix of fish byproducts and forest fines. Let's see what the NPK is. It's 2-0-0, so very low. He's trying to figure out how long that would take.
Jack: So that's adding 2% nitrogen. Nitrogen can be very tricky as well because although we're adding nitrogen, it has to convert over to plant-available forms, namely ammonium nitrate, ammonium nitrogen, and nitrate nitrogen. And these two, they call it mineralization. So what's really happening is the soil microbes are helping to convert that organic N over to mineral N. That's the part that's soluble and the plant can take up.
However, if it's soluble, that also means that dissolves in water, and water can leach it away. So nitrogen management is very difficult, because applied to the surface in the right conditions, it can gas off or volatize into the atmosphere. If converted to nitrate and soluble, it can leach away or it could simply run off the surface.
So we do have to pay most attention to how we're applying nitrogen to any crop that matter. However, the product you looked up there, Susan, at 2%, and very organic-y in nature, meaning carbon high organic matter, it would very likely release well and dissolve into the soil.
[00:20:29] Challenges in Nitrogen Management
Susan: So let's talk a little more about nitrogen, because that is the one really key nutrient that fruit trees and other plants need, but it doesn't seem you guys are able to soil test.
Tell me about that.
Jack: We can test for it. However, as I mentioned or alluded to there a minute ago, testing the total nitrogen doesn't tell you how much will be plant-available. So if we test nitrate nitrogen, and the chemical formula is NO3, that's the soluble form that the plant takes up into the roots.
If we test that today, but you get a two inch rainfall, we can't predict how much is going to be left after the rain. The best way to manage nitrogen is not based on the soil test, but rather apply the amount that particular plant needs through the growing season. So something like, for example, a radish. Very small, grows very quickly, doesn't require much nitrogen. Something big and lots of vegetative growth like a pumpkin plant. It's going to need a little more nitrogen.
So knowing the amount that your plant will need through the year, and if there's a best way of applying it, it would be a little bit every week through the year. But that's sometimes not practical. So we have to find the nice balance of making it practical and efficient.
Susan: Nitrogen in comparison to other nutrients though, doesn't it just sometimes just evaporate away?
You can have nitrogen in your soil in the morning and it's gone by the afternoon, whereas other nutrients are a little bit more stable?
Jack: So many of the nutrients, so for example, what we call the cations, those are the positively charged particles. Potassium, magnesium, calcium, they're positively charged.
And most soil, especially the clay portion, is negatively charged. So you have like a magnetic attraction where they just wanna hold on. So that's what we call the cation exchange capacity, meaning the more clay in the soil and the more organic matter, the greater the ability for that soil to hold those positively charged nutrients.
[00:22:34] Understanding Nitrate and Nitrogen Loss
Jack: Whereas in the case of nitrate, it's negatively charged. So a negative and a negative don't attract. And given the fact that it's soluble, that's why we can lose nitrate nitrogen through leaching.
[00:22:46] Complex Forms of Nitrogen
Jack: There's many complex forms that can happen with nitrogen: immobilization, denitrification. Immobilization is what many of your listeners would've heard.
If you apply a woody product to the soil, it ties up nitrogen. That's because it's high carbon. The soil bugs are trying to decompose that and they need nitrogen to do so. They rob it outta the soil. So the technical term is immobilization, but it's essentially taking nitrogen outta the system, which will eventually release, but it's not of any benefit to the plant.
Susan: Okay. A few more. We've got lots of questions today, so we'll move through them. Yeah. Really great questions.
[00:23:25] Listener Questions: Apple Trees and Sugar Levels
Susan: So here's the question from Eric. Thanks for the podcast. Lots of good info for apple trees. Old timers would check the sugar levels in the leaves and then decide on how much sugar or molasses water to spray.
Can you please explain more about this?
Jack: Yes. So there's also something called brix testing, which is the sugars. Now, the assumption that you can test sugar in the leaf and then apply a sugary product like molasses, it doesn't quite work like that.
So keep in mind, sugars are like a carbohydrate. They're made of carbon and hydrogen and oxygen. Those are the three primary nutrients. We don't think of carbon, hydrogen, and oxygen as nutrients because all those nutritional needs are met through the soil and the air and the water. Plants really are little chemical factories. They're taking that sunshine and the carbon and the hydrogen and making all these things. Sugar is one of them. Measuring them might be a benefit. We don't test for that in our lab. We're looking more at the individual plant nutrients as opposed to the ratio of compounds within the plant, because that would get very difficult to manage.
And maybe if you remind me later when we talk about plant tissue, we'll talk a bit about ratios too.
Susan: Okay. Sounds good.
Let's see, we've got one more. This is from Josh.
[00:24:50] Protecting Soil Health
Susan: So Josh writes, what can we actually do every year to protect our soil?
We would not want another dust bowl like down in the States in the thirties. I live in Peterborough, Ontario. Thank you for your answer, Josh.
Jack: Great question, Josh. So, many of us think of the soil as just something we plant into. And in the case of trees, we think of planting a tree and let it fend for itself, right?
But really, the soil is an ecosystem and we really need to have it protected and covered year round, if possible. I've heard it said that some of the traditional practices of harvesting a crop, and then plowing soil, and leaving it bare. That'd be like us humans standing outside all winter bare and cold and hungry.
Keeping in mind that the soil is full of biological life, the more we have something growing all the time, then the more that biology is sustained. There's always pros and cons though. So things like adding an organic amendment like a compost and working it into the soil, that's a good thing. But the very act of opening the soil to work it in is exposing it to oxygen and accelerates the decomposition process.
So I think the short answer there for Eric would be, keeping coverage at all times. So whether it's grass under trees, or a mulch, it keeps the environment more hospitable for soil microbiology. Yes. Always remember the soil is an ecosystem. It's not just dirt.
Susan: Yep, absolutely. And actually, I spoke to a grower who grew the best greens and she said over the winter, she just took all her leaves and weeds that she'd collect over the growing season, and she would pile it on top of the soil and just leave it there for the winter.
[00:26:51] Plant Tissue Testing Explained
Susan: So Jack, tell us a little bit about plant tissue testing. Like when would we do that? Do we only do that if we see our plant's leaves are not doing too well? When is it appropriate?
Jack: Well, in fact, the fruit specialists would say that a tissue sample is the way to come up with recommendations for nutrient use on permanent crops: the fruit trees, vines, and berries, for example. As a soil guy, I like to see a soil test, and it's always the best way to start to know what the underlying fertility is.
But as you mentioned, the tissue analysis gives you a snapshot of what the utilization of the soil nutrients are. How well the plant is taking them up. So a tissue test provides tests on each of the individual nutrients, and it also tries to compare it to what is expected to be a normal range so that you can see if it's relatively high or low.
But another good strategy to take, is if you see obvious differences across your plants, say one that looks dark green and robust, and one that's a little more pale or struggling, then taking the sample from each and comparing the two is often quite revealing.
Susan: So you would essentially, in that case, have to do two tests.
You'd send them in two different envelopes or two different packages. You package the healthy tree in for one tissue test, and the unhealthy tree would be in a second test.
Jack: If that's the case that you're faced with. Now, if you have trees that all look equally well, then one sample would suffice to get an idea of what the nutrition of those trees are.
However, if you do see problems, it's sometimes very revealing to have that comparison because you would have essentially the same plants in the same environment, same soil, same weather conditions. So seeing if one was higher or lower compared to the other might give you some insight into why those differences are occurring.
Susan: So we have an email here now. This is from, Lisa. hi. Fantastic show today. I'm learning quite a bit today, listening to you from Philly, Pennsylvania. Happy planting. Thank you very much, Lisa for your email.
So back to tissue testing. For instance, let's say you see that the leaves got chlorosis.
So the leaves on your plant or tree, they're turning yellow. You don't know why. You look at the soil test. What will give you better information as to why the chlorosis is happening, 'cause it could be a symptom of various different problems? Could it not?
Jack: Yeah, of course. And especially with chlorosis, because so many things can cause yellowing of the leaves.
The tissue tests should be able to narrow it down, and maybe it's multiple nutrients that are deficient. We also have to remember, I don't want to not mention this, that we can't just take any leaf off that tree. It should be specific leaves. Some nutrients are more mobile within the plant than others.
So nitrogen, for example, can move from the older leaves into the newer leaves, whereas other nutrients are very static. Once they're there, they don't move around. So because of that, we want to take the leaves that are the best representation of the plant nutrient concentrations. And that's usually by sampling the most recently fully developed leaf or the newest full-size leaf.
It's usually back from the tip of the growth. A few leaflets or about a foot back from the very tip of the growing branch.
Susan: Okay, so we're not taking the fresh little leaves at the tip. The little tiny ones. We wait till they're full size. Now, is leaf tissue testing only for trees? Or, if you are worried about a tomato plant, would it ever be worth doing?
Jack: Yes. If you're willing to manage nutrients in season, then tissue collection and testing is a good way of doing it. That rule of thumb applies to most plants. The most recent fully developed leaf.
But some plants differ, right? So a cabbage, for example, it's the fullest "wrapper leaf" they call it.
We do have a guide we could provide that helps people understand which leaf is the best one to collect. And we also need a lot of leaves, not just because. Representation. One leaf doesn't speak for your whole crop, but also we need enough to dry down and to grind and perform the various tests on.
So we've had where people will send a single strawberry leaf. We really can't do anything with that. We need about 200 grams, which is a good handful. I often tell people a third full paper lunch bag is about how much material we need. Once we dry that down, it's very little dry material.
Susan: So we've been talking a lot about these high tech tests that labs provide.
[00:31:55] Soil Testing Kits: Are They Worth It?
Susan: If you go online, there are a million different soil testing kits available. Are they any good? I actually got an interesting message on Facebook. I'm gonna read it to you. So this is David from Michigan. And he writes, I tested the soil around my property for the first time several years ago, and then tested it again a year or two after the first.
The results were the same. The second time, my soil is nitrogen deficient like zero, but plentiful and potassium and phosphorus, and the pH is fairly neutral. Therefore, I realized it just doesn't change all that much. I supplement with lots of low release nitrogen, where it's needed, and it's helped a lot, particularly with my lawn.
And he writes, perhaps it would make sense to test my soil again at a frequency about every five years. But when I ask David, I said, which lab did this test for you? Because I was quite surprised that he got such specific results for nitrogen and he was using a test that he got online. It's called the Luster Leaf Rapitest.
It's a soil testing kit that's $15 and it tests your pH and it tests the NPK. So what are your thoughts on these kits online?
Jack: There are many kits that can be a very quick and inexpensive snapshot. pH is fairly accurate test with the kit. Some of the other ones that are doing nitrogen or an estimation of nitrogen based on organic matter, or they say they can do a phosphorus of potassium.
They're not bad. but. Kits are about $20. A lab test in the laboratory, with quality control in place and approved methods, is about $20 depending on what you get tested for. Obviously the more tests, the more expensive. So I think that a lab test might give you more repeatability and more accuracy.
Now, that said, David was right, that soil fertility doesn't change that drastically from year to year. I mentioned in the before the break that the more clay in the soil, the more nutrient it can hold. So a clay type soil will change less dramatically from year to year. A sandier soil that doesn't hold nutrient as well, will change more.
So our general rule of thumb for soil sampling and testing is about every three years. If it's a sandy soil, you might want to do it every two years. The question mentioned five years. That's probably adequate. What we don't wanna see is people going 10 years or more between testing because that you can start to lose sight and lose track of some of your fertility levels.
Susan: Interesting. Okay. We have an email here from Paula. Hi. Thanks for the info today, and does Jack have an informational website? Thank you.
Jack: Good question. So Jack does not have a website. SGS, the company I work for, is a global company. They do have a website, sgs.com or sgs.ca.
The challenge, though, that we are so big, offering so much testing to so many industries around the world, it's difficult to find things that are specific to what we are doing in our laboratory in Guelph, Ontario. That said, you can go online, you can find some things. We also have some rebranding underway.
We are going to be called the Crop Science Division. You can see my background, the Health and Nutrition business of SGS. So coming soon, we will have some new websites, new branding, and we do intend on having more informational and interpretive type articles so that people can better understand their soil and tissue tests.
Susan: I want to ask you now, about choosing a lab.
[00:36:00] Choosing the Right Lab for Soil Testing
Susan: Because there are labs everywhere. We've got a lot of listeners from the states, we've got listeners from Canada.
Do you just pick a lab that you like the sound of, or what's the best way to choose a lab for your situation?
Jack: In the case of soil testing, as I mentioned right off the start, because of the regionality of soils, here in Ontario, high pH, high calcium soil, we call them calcareous. Our neighbor Quebec, has very low pH soils and they use completely different methods.
So from Ontario West, the western Canadian province is much of the Great Lakes Basin, they use similar methodology. The US Midwest, Northeast, there might be different tests that are referenced to local test plots and research plots.
We've had some listeners I've heard from Manhattan and Philadelphia. If they send me a sample, they're going to get Ontario results in Ontario recommendations, and probably not as specific as if they went to, say, Rutgers University in New Jersey.
So when picking a lab, make sure that they're local so that they're testing your soils appropriately. Accreditation to know that they're running methods that are repeatable and have quality behind them.
And also that they have recommendations because knowing what the test value isn't that informative. You need to know what to do next. Something like tissue testing is much more universal that could go to many different labs.
Susan: Fantastic.
[00:37:39] Conclusion and Farewell
Susan: Thank you so much Jack, for coming on the show today. I think that the listeners will understand why I invited you because it's really difficult to talk about soil in a manner that people can understand, and I find that you're really great at making things very clear and easy to understand. So thank you so much.
Jack: Not a problem. Thank you. And I hope we achieved that, and happy growing.
Susan: Happy growing, everybody. So goodbye for now to you, Jack, and thank you from all the listeners. And we'll wrap up the show now.
Thank you so much for listening. You take care and we will see you next time.