How To Read and Interpret a Soil Test Kit
Reading and interpreting a soil test has been made overly complicated by the old guard in lawn care and it doesn’t have to be that way, especially for a DIYer. You have one lawn to learn and having soil test data should bring you more confidence, not confusion.
The key is to take it at face value, and not overcomplicate it. No matter what you read below, come back up to this phrase and re-read it: “Take the data at face value and do not overcomplicate it.” That’s it.However, if you are someone who wants to dig into the science behind the test, I conducted an interview with the founders of Predictive Nutrient Solutions. They are the lab that processes our tests for us. Check out the INTERVIEW: Predictive Nutrient Solutions :: Makers of MY Soil Test.
Now, before we get into soil testing too deeply, let’s first understand why we even perform a soil test in the first place.
Fertilizers Provide Nutrients
When you test your soil you are looking to understand what nutrients exist in your there naturally so you can add those that are missing. All soils have some nutrients in them, just at different quantities. Our test will tell you what is currently available to your grass plant in real time, and then your job is to add what is needed. Here are the nutrients that grass plants need and how we classify them:
Macronutrients: Nitrogen, Phosphorus, Potassium, Sulfur, Calcium, Magnesium, Sodium.
These are the primary macronutrients your lawn will need. The reason they are called “macro” is because they are needed in larger quantities.
These are all important but the most important 3 (generally speaking) are Nitrogen, Phosphorus and Potassium. If you look at a bag of fertilizer you will see 3 numbers on that bag. These 3 numbers are known as the “analysis” and they represent nitrogen, phosphorus and potassium. They are expressed in percentages. Let’s look at an example bag:
What this is telling you is that 24% of this bag contains nitrogen and 6% contains potassium. So out of all of the thousands and thousands of granules (called ‘prills’) in this bag, 24% of those are nitrogen and 6% of them are potassium. Very generally speaking, these 3 elements are the most important when it comes to healthy plant growth. All of the others are important for sure, but these are the primary.
Micronutrients: Iron, Manganese, Zinc, Copper and Boron.
These micronutrients are also important but are just needed in smaller quantities. In other words, the plant doesn’t need as much boron to get it’s fill when compared to nitrogen. But don’t make the mistake of thinking the micronutrients are not important, because they are. It just takes a lot less of them to get the job done.
Now before we go too far: Your grass will not die if it’s lacking or even missing a couple of these. However, if it’s lacking or missing too many of them in certain combinations, it will be weak and frail.
Nitrogen for example: if your lawn doesn’t get nitrogen, it’s going to be extremely weak and it will not grow. This is why you will hear me say often that “nitrogen drives the bus.”
So for us, we apply these fertilizers and they can come in bags or in liquids. In this guide I;m going to talk mostly about granular fertilizers because these are what 95% of DIYers use. Liquids work great too but the market bares out that DIYers prefer granular so I’m mostly sticking to those when I talk about “fertilizer.”
The Different Types of Lawn Fertilizer Applications
In my teaching, I break things down into 3 loose “types” of applications of products that we make during the season. Those are “macro-ferts” “micro-ferts” and “bio-stimulants.” All 3 of these work together to give your soil and your turf what it needs nutrient-wise.
"Macro-Ferts" | Macronutrient Lawn Fertilizers
These are primarily focused on macronutrients and they focus on the big 3: Nitrogen, Phosphorus and Potassium. You should plan to apply a macro-fert about every 4-5 weeks during the growing season.
"Micro-Ferts" | Micronutrient Lawn Fertilizers
These are more supplemental and are usually going to be riding along with other stuff such as bio-stimulants.
These are designed to improve soil health. Sometimes they have nutrients included, other times they do not.
Some macro-ferts also have micronutrients and bio-stimulants included. Some micro-ferts also have a small amount of macro-fert or bio-stimulant included. Some bio-stimulants have macros and micros in them too.
The point is that there are overlaps and that is a good thing.
Nitrogen Drives The Bus
One thing I want to point out here and focus on is nitrogen. Everytime you apply a “macro-fert” you want to be sure it has some nitrogen included in it - that is the first number of the 3 numbers on the bag called the “analysis.”
The higher this number, the more nitrogen is in the bag.
Nitrogen drives the bus and ALL of the other elements ride on that bus but without nitrogen driving them, they go almost nowhere.
In all of my plans, I recommend you apply a macro-fert every 4-5 weeks or so. No matter what your grass type, apply macro-fert every 4-5 weeks and ensure it has at least some nitrogen in the analysis. Nitrogen drives the bus.
So right now, mark this down: Whenever you apply a macro-fertilizer (every 5-6 weeks) you want to be sure it includes some nitrogen. I do not care what your soil test shows - low or high or in between, be SURE to have nitrogen in the mix. Got it?
Remember: Nitrogen drives the bus.
Soil Test Results - Mindest
From here onward, I’m going to get pretty and show you exactly how to take your test and choose fertilizers that will help correct the results as they sit currently. But first I want to adjust your approach and mindset. When you get your soil test results back...
Don’t Stress Over The Results
For the majority of folks, when they get their test back and start looking at the result graphs, they immediately think something is wrong. They look at areas where they are very low or very high and they get the idea that their lawn is going to die. I am not exaggerating - people get a heightened sense of urgency that causes them to have anxiety.
So I always recommend: no matter what your soil results show - go look at your lawn. Obviously lawns are brown (dormant) in winter and some lawns go dormant in summer too, but assuming it’s not normal dormancy, is the lawn dead? Probably not.
Sure, you may have some weeds and thin areas and the lawn may not be super dark green, but you still have to cut it every week or so right? That means it is growing.
Realize this: grass on the side of the highway is green during the rainy season and no one cares for it properly. It gets bush-hogged by dirty mowers once-a-month and giant scrap piles are left on top but it still grows, year after year.
And you know what else? Grass is resilient! Guess what the first thing to regrow is after a forest fire? That’s right, it’s the grass.
Soil Tests Are Not Like Grades In School
So don’t look at the soil test like a bad grade in school. If areas are bad, no one is going to punish you or come down on you. The current state of the soil literally “is what it is” and you can only get better. Look at your soil test results as if you are starting a brand new school year and this is your baseline. You can only improve from here.
And sticking with my school analogy, this is the other mindset adjustment I want to help you make. Since the soil test isn’t a grade, you do not have to bring it up super fast before the end of this quarter or semester! In fact, you can correct it on whatever time scale your time and budget allow. School doesn’t end when it comes to your lawn. Season after season, you literally keep “schooling” your lawn and soil.
For some reason though, folks look at their test results and go out looking for one miracle fertilizer that will fix it all in one application so they can feel better. But that isn't how it works for us. Our crop is perennial meaning it’s there year-after-year and is never harvested. Because of that we can apply nutrients to correct the soil over time.
This is much different than what we do when you consider the lawn that is at your house now will be the same lawn that is there in 10 years. Big difference in strategy.
So get that straight now too: there is no miracle application you can make and you do not have to correct your soil fast or in a hurry. Just move in the right direction with every application you make from now until the end of the season and even into the next season, just keep moving in the same direction.
(note: you do not have to test your soil every year but many people do. You can get away just fine with testing every 2 years.)
Soil Tests are Not One and Done
But that isn’t the case. Instead, think of your soil test as a new setpoint each year, not a finish line.
Let me use the analogy of a blood test. You go to your doctor and get your blood drawn and he/she tells you that you are low in iron, potassium and vitamin D. So you go and start eating foods rich in these nutrients, you may even be given a supplement.
When you go back in 6 months and your levels are better, do you stop eating those foods or taking those supplements? No, you still keep with them knowing that you are at a good set point to continue forward. If you were to stop with these nutrients your blood test would eventually show low in those nutrients again.
The other thing to consider here are the nutrients that you are NOT deficient in. Sometimes when folks change their diet to accommodate or improve a blood test, this change now gives them less of some of the nutrients they were getting from their previous diet and the second test can show that they are not low in those.
See how that works?
Key Point: A soil test is not an end point, it’s a starting point and each year gives you a new starting point from which to work. If you want to test every two years, that is fine too - just get a new set point every two years.
You know what else? Sometimes your blood test results can be improved with lifestyle changes that have nothing to do with eating or taking supplements. Exercising, for example, solves a lot of problems on it’s own because it causes your body to release certain hormones or enzymes.
Same goes for the lawn: a lifestyle change that will be super beneficial to all of you is to start mowing more often. Here is a video talking about that in great detail with awesome analogies.
If you have been bagging your clippings, just changing to mulching will help you retain more of your nutrient inputs too.
- A soil test is not a grade of your lawn - it’s not going to die
- You don’t have to be in a hurry to improve your results - there is no miracle application.
- You are not trying to get to a finish line - instead you are just course correcting each season.
Remember, a soil test, no matter if it is your first year, second year or 10th year, is directional data. Look at where you are deficient, and head in the right direction for the entire season.
How Does Your Lawn Look?
And never forget to look at your lawn! No matter what your soil test shows, if the lawn looks good and is growing, then you have to know you are on the right track. Never discount this data either. It matters.
If you throw down a high nitrogen fert like 24-0-6 Flagship (with 3% Iron), I can guarantee you that you are going to see an improvement in your lawn, as long as you are watering. Lawns need adequate water in order to grow!
So if you are watering (or you are getting regular rain) then no matter how bad your soil is, you will see a difference if you apply a high nitrogen fertilizer. The lawn will look better and you should take that as a sign that “hey I am making some improvement here!”
Over the years though, it seems like some folks still seem to want to focus on how bad the results of the test are and not even look at the lawn itself. Don’t do that. Look at the totality of the situation.
A lawn that is green and has responded to your fertilizer application is on the right track. Use the test data to make things even better, not as a way to think that something is wrong.
Can I Get My Soil To Retain More of What I Add?
I mentioned above a third type of product that I like to add into my programs and those are “bio-stimulants.” These make everything else work better by improving soil quality.
There are ways to get your soil to a point where it can hold more nutrients and also make better use of what it’s given naturally from things like root cycling, earthworm poop and even you mulching (recycling) your clippings when you mow. There are also ways to make your soil more “attractive” to nutrients which means it can hold them longer.
Typically, this means improving your soil by increasing the amount of carbon. I’m not looking to get too complicated here so just know, increasing soil carbon is a good thing. Carbon sources include but are not limited to:
- Organic nutrients - Organic Fertilizer, Milorganite or fertilizers with biosolids in them.
- Humus - Humic12, Spoon Juice
- Biochar - Soil Mastery 5-0-0 - contains Humic, Biochar + More!
You will find that all of the programs I recommend will have a lot of information and recommendations about fertilizers, but I always include a “base layer” of added bio-stimulants or natural elements that increase soil carbon along with them.
As mentioned earlier, sometimes you can get macro and micro ferts that contain bio-stimulants. These are important tools in correcting your soil.
pH Is Important
One other piece of data you will find on your soil test is the pH. Those two letters, pH stand for 'potential of hydrogen' or 'power of hydrogen' and your pH is signified using a scale that specifies the acidity or basicity of your soil.
Here is a complete article on How To Fix Your Soil pH and What Products To Use
If your pH is showing high (alkaline) or low (acidic) then that is something you want to begin addressing right away. Once again, the lawn is not going to die and you don’t have to fix it all with one miracle throwdown, but for sure, you want to make it a priority to move that needle.
When your pH is off, nutrients that are naturally in the soil can become “locked out” meaning they are there, but they are unavailable to the plant. Moving your pH into the normal range can unlock them.
Incorporate products that will move your pH in the right direction. The best times to apply these are spring and fall. Use MAG-I-CAL® PLUS Soil Food for Lawns in Alkaline & Hard Soil to lower pH and MAG-I-CAL® PLUS Soil Food for Lawns in Acidic & Hard Soil to raise pH.
Choosing Fertilizer Based On Your Soil Test
Now that we got all of that out of the way, it’s time to make a strategy based on the data you get from your test.
This is an actual sample taken from one of my lawn projects. I’m looking at the graph and making some decisions. This is really the only part of the entire test result that you need to look at if you want to keep things clean and simple. See where you are lacking and choose ferts (macro or micro ferts) that help move you in the right direction - here is my thinking process:
The very first thing we want to look at is the pH. While it’s right there on the border of the range, I’m going to make the decision to start moving it down. This is the very first consideration I will make and I will choose this product which I will apply twice in spring.
Will that give me a total fix? I don’t know. Again, I am just moving in the right direction, not trying to “cure” a problem. Making two applications of a product made for alkaline soils gets me on the right track for sure.
Now, right around the same time I will apply my first application of macro fertilizer. Remember, “Macro ferts” are those that are primarily focused around N-P-K which are the 3 numbers on any bag of fertilizer you see. These 3 numbers represent Nitrogen, Phosphorus and Potassium and are known as the fertilizer’s “analysis.”
For this one, since I need N, P and K according to my soil test, I am going to choose the 12-12-12 Starter Fertilizer (with 3% Iron) and Bio-Nite™ - Granular Lawn Fertilizer. This will supply nice amounts of all three of these macronutrients that I am lacking. I will apply according to the directions on the bag. Regardless of how low I am in any of the nutrients, I’m going to follow the bag suggested application rate.
AGAIN, I am not trying to “throw down extra heavy” to fix this in one application - instead I am getting a macro-fert that takes me in the right direction and I will just follow the suggested rate on that fertilizer. No need to go crazy.
I will apply my pH correction first, water it in, then apply my 12-12-12 a week or so later. You could do them on the same day if you wanted to, but I like to see a product work a bit first - to see if there is any visual change after I apply it so I separate these two by a week just for that.
Now there is a bonus here - remember how I told you some macro-ferts also have some micros int them? This is one of those cases. My 12-12-12 Starter Fert has some other goodies packed in. Here is a screenshot from the label:
I used red lines to show you some of the micronutrients that I have included in this fertilizer and those happen to line up with what we need on our soil test too. See how the percentages there are much much lower? That is because these are micronutrients so they are needed in much lower quantities, yet they are still needed and this fert supplies them.
I have actually formulated all of the Yard Mastery granular fertilizers with these micronutrients. If you get Flagship, Starter, Stress Blend or Double Dark - they all have these extra micronutrients included. In this case, they line up very nicely with what I need.
This has come up pretty clean so far right? I’m applying something to move my pH and I’m also applying something to give me some nutrients I need. Within a week or so of these applications, I’ll be seeing some nice greenup for sure.
But we still have some work to do because this is only the first application(s) of our strategy. Remember, just because this all lines up it doesn’t mean we are “one and done” - it just means we are heading in a good direction.
With every strategy I recommend, I have a “base layer” of bio-stimulants that are applied along with and in between our macro-fertilizer applications.
Generally speaking, you apply macro-fertilizer every 4-5 weeks or so. Remember, I applied a pH adjustment application and a macro-fertilizer app pretty close together and that got me off to a good start, but I also want to apply bio-stimulants (add carbon) because those help to improve the overall quality of my soil so that can hold more nutrients and make the ones I apply work better.
The thing about the bio-stimulants is that some of those will also have nutrients that I need blended into them. So by applying a bio-stimulant every month as a “base layer” to my macro-fert, I am not only improving my soil, but I am also adding some of the micros I need.
Here are 3 examples. These are bio-stimulants that you would apply every month or so in between your macro-fert apps. These add carbon to the soil but also include some nutrients so they are combination products - they are “micro-ferts” and “bio-stimulants” combined:
0-0-2 - Micronutrient Supplement with Bio-Stimulants
Included in 0-0-2 Microgreene are:
And would you look at that? All of those are ones we need!
The other things that are inside this jug are the bio-stimuants themselves. Humic acid is the main one and it’s the carbon source but this jub also has some sea kelp in it which are hormones that stimulate healthy rooting in the turf.
Now the amount of this you put down every month or so is low. It’s 6oz/1,000 sq ft. So this isn’t going to be a huge lift of nutrients but again, it sends you in the right direction and that is the key.
5-0-1 Spoon Juice
I love Microgreene. But some of you may want something that flows a little easier. If you are using a hose end sprayer to apply your liquid bio-stimulants, you want to choose Spoon Juice 5-0-1 Liquid Fertilizer and Bio Stimulant with Humic Acid and Kelp over MicroGreene. MicroGreene can get a little gritty.
Spoon Juice has high amounts of bio-stimulants in it and some micros. It also has a small amount of nitrogen to stimulate intake of those nutrients. If you are new or want a simpler solution, you want Spoon Juice. If you are more advanced and are good with using a battery sprayer, go with MicroGreene or you can use both back and forth.
Another thing to mention about Spoon Juice: some of you are going to feel like you just want to spray something almost every weekend. Trust me, once you get started working on, and improving your lawn, you are going to get the urge to spray, often. Spoon juice is perfect for this. At the low rate of 3oz/1,000 sq ft you can apply it every single week if you want.
5-0-0 Soil Mastery Granular Bio-Stimulant
This is a new micronutrient and bio-stimulant granular that we just released. This is an awesome soil amending product because it contains a ton of carbon in the form of humic acid and bio-char. It also has some kelp in the mix.
But we also had some nutrients formulated in and those are:
So you can see this product will help add some of the elements you need too but there is one you don’t need and that is calcium. What does this mean?
So if you have a choice, then you’d choose the 0-0-2 MicroGreene instead of the Soil Mastery. However there are other things to consider and one is your own ability. MicroGreene is a liquid concentrate and you have to mix it in water and apply it with a sprayer. Many many folks I talk to do NOT want to go through this hassle. They prefer granular products and that is where the Soil Mastery becomes an option.
So if that is you, even though your calcium is high, you can still use the Soil Mastery. Adding a bit more calcium is NOT going to hurt anything. So don’t worry. You see, not everything works out perfectly when it comes to these things, so get the best possible product you can find and go with it. If it isn’t perfect that is ok.
Now as the year goes on I will still be applying my Microgreene, Spoon Juice or Soil Mastery every 4-5 weeks or so and also my macro-fert. Sometimes I will do them both on the same day, other times separately - it doesn’t really matter.
Now for the second macro-fert application of the season I will choose to use 24-0-6 Flagship (with 3% Iron) and Bio-Nite™ - Granular Lawn Fertilizer. This is also a good choice because it has the nitrogen and potassium I need, plus it has the micronutrients riding along too. (all of the Yard Mastery fertilizers have the same micronutrients in them as you see above with the 12-12-12 Starter Fertilizer).
It doesn’t have the phosphorus I need but that’s ok because for many of the other elements it still keeps me going in the right direction. Remember, you do NOT have to hit every element with every app - just head in the right direction.
For the next application (4-5 weeks later), I may choose to apply the 7-0-20 Stress Blend (with Bio-Nite™) - Granular Lawn Fertilizer. This has some nitrogen, but really pushes the potassium. And as I mentioned, it also has the same micronutrients as the others.
Can you see how I am moving in the right direction? Also keep in mind that all during this time I am also applying my MicroGreen, Spoon Juice or Soil Mastery which is also adding more of what I need.
I am also going to be looking at the lawn and seeing what I like. If I liked the visual result I got from the Flagship better than the Stress Blend then I will go back to that. I will also probably go back to the 12-12-12 Starter Fertilizer at some point just to get some added phosphorus in there since it’s showing I need some.
See how this works? It’s really just that simple. Choose ferts that line up as closely as possible with what you need in your soil and move in that direction.
Is This Complicated?
STOP: Confused? You may need some basic training to really get the this to all click for you. Trust me, I’ve been teaching DIYers online for over 10 years - longer than anyone else - and I know that even with all the detail I provide and analogies and everything else, some people still just don’t get it right away. If that is you, you are NOT alone.
Not everyone has a born instinct for this stuff. When I go fishing with guys who are true fisherman, I annoy them because I have no instinct for fishing and I fumble around and don’t set the hook right and lost fish right at the edge of the boat - because I do things wrong. I’ve been fishing for years and I still just can’t get it right.
Some people are like this with lawn care. Only difference between fishing and lawn care is that I am fishing with my buddies who can bust my balls over my lack of instincts but when it’s you and your lawn you just have to fumble around alone - which is good and bad.
But you don’t have to be alone any longer - I have created some basic training for you where I take your through DIY lawn care, step by step and it’s called Yard Care Boot Camp. Check it out here.
Just for fun, let’s look at one more test result and make some decisions:
So on this one, I also have a pH challenge - this time I need to raise it. So I will get to work right away, not matter what time of year I’m getting started and apply a product like this one to raise the pH. I will make 2 applications of Mag-I-Cal® for Lawns in Acidic Soil in the first couple months regardless of what else I do.
I will also get started with some macro-fert but in this case my phosphorus is high. Now, I am not going to be concerned over that high phos, but if I have a choice, I am also not going to add more. So here I will choose either 24-0-6 Flagship or 7-0-20 Stress Blend to give myself macros I need plus some micros.
For my bio-stimulant choice I’m going with Spoon Juice because it has iron which I need, and it also has some sulfur that I need as well as a bit of N and K. It’s perfect to help fill in some of the gaps.
For the next few applications of macro-fert over the season, I will switch back and forth between Flagship and Stress Blend and keep that Spoon Juice going down.
It’s really that simple, all of those should be taking me in the right direction, easy as can be.
I hope this guide has first off helped educate you. That is my goal first and foremost. Secondly, I hope that you are now ready to take action and realize that soil testing is NOT complicated and in fact, is pretty dang easy!
Now a few questions people often ask:
Q: If I have not taken a sample yet, can I still start applications?
A: Absolutely. Take your soil samples now and send them in. While you are waiting (takes about 6-7 days for results) go ahead and order 24-0-6 Flagship and throw that down. You will already be seeing results and Flagship isn’t going to harm your strategy going forward.
Q: Can you soil test anytime?
A: Yes you can. Hot soil, lukewarm soil or frozen soil are fine - as long as you dig down just below the root zone, to the area of soil that is about 4” down, and you can pull some of the soil, you can sample. This can be difficult when the ground is frozen, FYI. But the actual temperature of the soil does not matter.
Q: If the soil is wet or dry does it matter?
A: No it doesn’t. Obviously it’s messy to pull soil samples in the mud so don’t do that, and trying to dig into dry hard clay is also not fun, but really the moisture content does not matter.
Q: When is the best time to sample soil?
A: You can sample soil at anytime of the year. Just be sure that you have NOT applied any fertilizer to the lawn within at least 45 days prior. This can contaminate your sample.
Q: How long after an application of fertilizer can I take a sample?
A: Wait 45 days after any fertilizer application to take a few soil sample.
Q: What if I can’t find fertilizer to fix all the problems I have?
A: Then just do the very best you can. You do not have to be perfect, you just have to be better now than you were a month ago.