Start Right to End Right: 3 DIY Soil Sample Tests to Perform to Insure Your Garden Is as Productive as Possible

When we reach the time that we are really gardening when it counts—when our home gardens have to produce all the vegetables we need because we can’t get them from a grocery store for whatever reason, we need to do more than throw some seeds in the ground and hope that they grow.  We need to do some homework first—soil science and chemistry homework.  The assignments are interesting and easy.  As a couple of bonuses, the results are more accurate than those obtained from using commercial kits, and you can get them on the same day, instead of waiting for days or weeks when using a service. 

Method #1—Taste Testing

Several times over the years I’ve read that farmers of old always conducted soil tests before planting.  Of course, they didn’t have fancy tests kits or Cooperative Extension offices.  They were on their own—just as we will be when society collapses.  These old-time farmers would put a bit of soil in their mouths, moisten it with saliva, and then determine whether it was sweet or sour.  Alkaline soil would be neutral or sweet.  Sour soil was acidic.  It was hugely convenient for the farmer because his soil test kit—his mouth—was always with him.  People today can conduct their soil tests the same way.

I am not going there.  And I don’t understand why they did.  Animals poop on the dirt, for Pete’s sake.  Maybe the soil taste-testing farmers are totally confident that any animal manures have completely decomposed, but I am most certainly not.  I just know I’d find a hunk of cat doo if I ever tried this.  And then there are all the worms.  I don’t need to go there.  I don’t need to go asking for trouble.  And you don’t, either.

Method #2—Baking Soda and Vinegar

This second test method is as accurate as the taste-testing method above, as well as being pretty quick and easy.

• Collect 1 cup of garden soil.
• Put ½ cup of soil into each of two containers.
• To the soil in the first container add ½ cup white vinegar.
• If it fizzes, the soil is alkaline, with a pH between 7 and 8.
• If it doesn’t fizz, do the next test.
• To the soil in the second container add about 2 teaspoons of distilled water.
• Add ½ cup baking soda.
• If it bubbles, the soil is acidic, with a pH between 5 and 6.
• If neither of the soil samples fizzes or bubbles, you have a neutral, balanced soil.

Unfortunately, while this method is just as accurate as the taste test method, it isn’t very specific.  You can’t tell whether your soil is slightly alkaline or acidic, or very much so. 

Method #3—Red Cabbage

This final test method is by far the most accurate—better even than the store-bought kits.  It takes less than two hours in all, and most of that isn’t even hands-on time. 

• Pour 2 cups of distilled water into a 2-3 quart saucepan.
• Add 4-6 chopped red cabbage leaves (about 2 cups).
• Simmer for 10 minutes.
• Remove from heat and let sit for 30 minutes.
• Strain off the bluish-purple liquid.  It will have a pH of 7—neutral.
• To test:
• Add 2 teaspoons of garden soil to a canning jar.
• Top with 2 inches of red cabbage water.
• Stir and then wait 20-30 minutes.
• Check the color.
• Reddish-pink= acidic soil
• Sea blue-yellowish-green=alkaline soil
• Purplish-blue = neutral soil

Figure 1.  Photo courtesy of anishsbioblog.wordpress.com.  This shows the range of color you can get using red cabbage as the indicator.  When comparing to your own results (which will have soil at the bottom and suspended particles in the solution sample being tested), be sure to compare only the shade and not the intensity of the color.

I tested seven different samples of soil from various areas of my garden and yard.  The three garden soil samples all registered about an 8.5 based on the colors and pH scale gradient above.  That was a little surprising to me, but it also perhaps explains why the previous owners’ garden looked so sorry.  Something I had attributed to lack of care because they were busy moving might be better explained by the fact that the pH of the soil was too high.

The four samples of native soil came in at about 7.5 on the scale.  This includes the area where the blueberries will be planted.  Since blueberries require very acidic soil to grow, we will have to amend that soil heavily.

Testing the pH of the soil seems like such a little thing.  We like to believe that if we till the soil a little, start with good seeds, add sunshine and sufficient water, our vegetables will grow.  I like to believe that for sure.  However, and unfortunately at times, that pH is critical.  The soil’s pH affects the plants’ ability to take up nutrients from the soil.  The wrong pH can make certain nutrients completely unavailable to some plants.  When they don’t get what they need, they die.  Just like people.  We can have loads of vitamin C or D, but if we’re missing out on something critical, like niacin or thiamine, we’re going to die, too. 

So do yourself and your family a favor, and test the pH.  Learn what your plants’ needs are, have some synthetic amendments on hand if possible, and start and maintain a compost pile.  Happy gardening!