It’s impossible tell if the soil is healthy just by looking at it, you have to some type of soil testing. Don’t worry, garden soil testing isn’t complex, time consuming or expensive. In this post, I will show you exactly how to test your soil at home using an inexpensive soil test kit.
If you struggle to grow strong, healthy vegetables and flowers in your garden, then there’s probably something wrong with your soil.
Plants that aren’t getting the proper amount of nutrients and pH levels won’t grow well, and will only struggle to survive.
Stunted growth, minimal or no flowers, vegetable plants that aren’t producing anything (or are only producing tiny fruit), and plant death are all common symptoms that your plants are not getting the proper nutrients they need from the soil.
What Are Soil Nutrients and pH Levels?
There are three main nutrients that are vital to the survival of every plant – nitrogen, phosphorus and potassium (N-P-K for short) – and each one plays an important role in the health of every plant.
You might even recognize the abbreviation N-P-K, those are the same numbers you see on the front of bags of gardening fertilizer.
The proper pH balance in soil also plays an important role in growing a healthy garden. Some plants require acidic soil (with a lower pH level) to grow and thrive.
Other plants will suffer or die in acidic soil, and need alkaline or neutral pH soil (with a higher pH level) to grow their best.
DIY Home Garden Soil Testing
If you’ve never tested your soil before, I recommend getting an inexpensive soil test kit that you can use at home. It’s quick and easy to do your own garden soil testing at home so you know exactly how to amend your soil.
Then you can test the soil again after you’re done amending it to make sure you added the correct amounts of everything, and to see if your soil health is improving.
Plus, when you have a kit at home, you can test your soil on a regular basis to make sure it’s always in balance.
It’s a good idea to test your soil at the end of every gardening season so that you can add your soil amendments before planting again.
Why Should A Homeowner Perform Soil Testing
Soil is where our garden plants get the nutrients that they need to sustain life.
And just like us, plants need a balance of the proper nutrients in order to grow healthy and strong, and to fight off disease.
They aren’t going to be able to produce tons of vegetables and flowers if they’re struggling to survive in unhealthy soil.
Even if your garden soil looks healthy, there’s no way to be sure it contains the vital nutrients that your plants need to thrive without testing it.
So, if you’re unhappy with the way your gardens have grown in the past, then the first thing to do is test your soil for nutrients and pH.
What Information Does A Soil Test Give You?
A garden soil test kit should tell you if your soil is deficient of any of the three N-P-K nutrients, and should also tell you the pH level of your soil.
But, if you’ve never tested your soil before, then I highly recommend buying a home test kit that will test the N-P-K nutrients in your soil, as well as giving you the pH level of your soil.
How To Test Soil For Nutrients
Your soil test kit should come with instructions for use, so make sure you review those first (especially if you have a different kit than I do) as they might be slightly different than mine.
My test kit came with four different containers for testing each of the main nutrients, pink for nitrogen (N), blue for phosphorus (P), orange for potassium (aka: potash) (K), and green for pH.
In addition to your test kit, you’ll need a few other supplies before you get started.
Soil Testing Equipment Needed:
- Soil test kit (for N-P-K and pH)
- Clean container (I used a kitchen bowl)
- Clean garden trowel or large spoon
- Distilled water
- Measuring cup (1 cup)
How To Collect Soil Samples For Testing
The first step for all four of the tests is to take a clean soil sample. Taking a soil sample is really easy, but you’ll want to make sure that your tools are clean first.
Use a clean trowel to take your garden soil testing sample (don’t use your hands), and also use a clean container or bowl to put it in.
If you don’t have a trowel that’s easy to clean, then you can just use a large spoon from the kitchen.
Remove any mulch or debris from the top of a small area of your soil, and then dig down about 3-6 inches into the soil to take your soil sample (the garden bed I’m testing is new, so there isn’t any mulch on top yet).
In order to do all four tests, you’ll need a little more than one cup of soil (one cup for the N-P-K test, and less than one teaspoon of soil for the pH test).
How To Test Your Soil At Home Step-by-Step
The instructions are identical for testing the N-P-K values, but slightly different for testing pH. So, below I’ll break down the steps for both types of tests.
I’ll start with the N-P-K tests, so set your pH tester aside for now.
Steps for the phosphorus, potash and nitrogen test kit (N-P-K):
Before jumping into the steps for testing the N-P-K levels, I wanted to give you a heads up that it takes a little longer to test the N-P-K values than it does to test the pH level.
This is because, for the N-P-K tests, you need to mix your soil sample with water, and let it sit until everything settles (which can take up to 24 hours).
So just keep that in mind when you plan to do your garden soil testing.
Follow the steps below to use the phosphorus (blue), potash/potassium (orange) and nitrogen (pink) test kits.
Step 1 – Mix soil sample with water: In a clean bowl, mix one cup of your soil sample with five cups of distilled water.
It’s important to use distilled water rather than tap water to be sure your test results are accurate (tap water can contain chemicals and minerals that can skew the test results).
Step 2 – Allow soil to settle: Stir or shake your soil/water mixture for a minute to so, and then let it sit until everything settles.
Remember, you might have to wait a while to move on to step 3. Also, it will take much longer for clay soils to settle than it will for sandy soils (heavy clay soils can take up to 24 hours to settle).
You want the testing water to be as clear as possible, so it’s better to give it enough time to settle than to rush this step.
To make it easy, I just let my soil sample settle overnight (I have sandy soil).
Step 3 – Fill test kit containers with sample water: Now, that everything has settled, make sure you don’t move the soil sample/water mix or disturb the soil at the bottom.
Fill both chambers of the N-P-K testing containers with your sample water up to the line towards the top. Your test kit should come with a little dropper to make it super easy.
Don’t fill them all the way to the top of the container though, you’ll need a little bit of headspace to shake them up after you add the test powder in step 4.
But you do want the water level to be above the top of the colored boxes (it’s really hard to see, but there is a very faint dotted line at the top of left chamber to indicate the water level).
Step 4 – Add the test powder: Everything that comes with your soil test kit will probably be color coordinated like mine is.
There are colored capsules that come with the kit, and these contain the garden soil testing powders that test each nutrient.
The color of capsule you need to use for each test matches the color of the lid for that test container (i.e.: purple lid/capsule for nitrogen (N), blue for phosphorus (P), orange for potassium).
I recommend doing this next part in an area where there’s no wind.
Carefully pull apart the capsules so that you can pour the powder into the left chamber of your test kit. You only want to put the powder in there, not the entire capsule.
Don’t let any of the powder get into the water in the right side compartment (that needs to just be the test water).
Be careful here, you don’t want to inhale the powder or get any of it in your eyes or mouth.
Step 5 – Allow test powder to dissolve: Put the cap back on the test container, making sure it’s on there tight so the water doesn’t get mixed between the two chambers.
Then shake the container until the powder is dissolved in the test water.
You may notice it changing color right away, or you might not notice anything.
Now you can let the N-P-K tests sit for 10 minutes before you read the results.
Steps for soil ph testing kit:
The soil pH test method is a bit different than the N-P-K tests, and it’s a bit faster too.
You need less than a teaspoon of sample soil to perform the test, but make sure you use the same steps for how to take soil samples for testing above to collect your sample (using clean tools, not your hands).
Follow the steps below if you’re using a home test kit to test the pH of garden soil.
Step 1 – Put your soil sample into the test container: Add a small amount of your sample soil to the left side chamber to fill it to the line (it’s really just a tiny bit).
I tried using the dropper thingy for this, but that does not work, so don’t do that. I found it easier to use a small (clean) spoon to get the dirt in there.
You don’t have to be too fussy or worry about getting dirt into the right side chamber.
And if you accidentally fill it above the line, then you can just pour out the extra. No biggy.
Step 2 – Add the test powder: Grab one of the green capsules for this test (or the one that came with the test you have).
Again, I recommend doing this part in a spot where there’s no wind. You don’t want the powder blowing away, or getting into your eyes or mouth.
You want to put only the powder that’s in the capsule into the chamber, not the entire capsule. So, carefully separate the capsule and pour the powder into the left chamber (right on top of your soil sample).
Step 3 – Add distilled water: Fill the rest of the left side chamber with distilled water up to the fill indicator arrow (this is where you can use the dropper thingy).
You can leave the right side of the container empty for this test.
It’s best to use distilled water for your pH test just in case there are chemicals in your tap water that will skew the test results.
Step 4 – Mix everything together: Put the cover back on your test and make sure it’s on tight.
Now you can shake the heck out of it to mix the soil and test powder with the water.
Let everything settle for about one minute before reading the pH test results.
How Long Does It Take To Get Soil Test Results
The thing I like the most about doing my own garden soil testing at home with a test kit is that it’s really fast (and easy!).
After preparing the tests, it takes about 10 minutes to get the results for the N-P-K tests, and only one minute for the pH test.
The pH test gives you almost instantaneous results, since you use a soil sample, and don’t have to worry about soaking it before hand.
The N-P-K testing takes a bit longer, since it’s more of a process to prepare your test sample, and you have to wait a bit longer to analyze the test results.
Analyzing Your Soil Test Results
After letting your tests sit for the recommended amount of time (10 minutes for N-P-K, and one minute for pH), it’s time to analyze your garden soil testing results.
To do this simply hold the test up to a source of natural light (not direct sunlight though) and compare the color on the left side with the color chart on the right.
It’s pretty easy to see if your soil is severely deficient in one or more of the N-P-K nutrients, because there will hardly be any color in the left chamber.
The darker the color on the left, the more N-P-K your soil contains.
You can see from my N-P-K tests (see photo below) that my soil is deficient in nitrogen (pink), sufficient in potash (orange), and has a surplus of phosphorus (blue).
Same idea for the pH soil analysis, compare the color of your sample on the left to the chart on the right. The color chart will show you how acidic or alkaline your soil is.
You can see from the results of my pH test (the green one on the right), that my soil is alkaline.
Now that you know the N-P-K and soil pH levels, you’re armed with the information that you need to properly amend your soil, and make sure you’re growing your plants in the best garden soil possible.
No more guessing, now you know exactly what you need to add to your soil to grow your best garden ever!
Garden soil testing is extremely helpful for gardeners of any level. After all, soil rich in nutrients is the key to growing strong, healthy plants.
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Share your tips about garden soil testing and improving garden soil in the comments below!