The “pH” is considered the master variable (kind of like an on/off switch) in soils because it controls many chemical and biological processes which include the amount of nutrients available to your plants. That means it is a pretty darn important factor when it comes to how well a plant performs. So, if your plants have poor or stunted growth and/or have pale or discolored leaves, you might want to check your soil’s pH. Whether it is either too high or too low, by properly adjusting the pH, a definite improvement in your plants health and happiness will occur.
What is the Ideal pH?
The winning pH number when considering a soil’s pH is approximately 6.5, which is slightly acidic. The reason it is favored is because this is the point at which most of our garden plants can most easily ingest their required mineral nutrients available in the soil. Of course there are a few plants in our garden that prefer a more acidic environment such as: blueberries, rhododendrons, camellias and even clematis. But as a whole, it would be a good pH to aim for.
That being said, if you look at the chart above it shows the influence of the pH on 11 of the nutrients available to your plants. You can see that your plants would still be in a safe zone (which is highlighted on my chart with a violet-mauve bar) with a pH range of 6.2 (slightly acidic) to 6.8 (very slightly acidic). Since I am always concerned with the wellbeing of my clematis I have opted for establishing a pH of 6.2. By doing so, I keep my clematis contented while still allowing the rest of the garden to obtain its needed nutrients.
What Is Your pH?
Back in the good old days when times were simpler farmers used to do a “taste test” to determine the soil’s pH for their crops. Yes, they would actually put a small amount of soil into their mouth. If the soil tasted (and smelled) “sweet” then it was deemed to have a high pH (alkaline). However, if it tasted “sour”, it was judged to have a low pH (acidic).
Fortunately for us we don’t have to sample a “dirt hors d'oeuvre” to be able to determine a soil’s pH. Today we have a much more reliable way to indicate our garden’s pH and that is to have it professionally tested. I might venture to say that this is a tastier alternative (wink). Yes, there are plenty of DIY kits out there, but if you are really interested in the most accurate results I would suggest you use a soil testing laboratory or see if your local County Extension field office preforms these tests. Along with the results of the test, they will educate you about how to fix any problems.
FYI, if you are in doubt about the advantages of using a commercial lab to test over a do-it-yourself hand held meter, I think the online article, pH Meters, Friend or Foe? clearly shows the discrepancy in results of the pH value between the two methods. Remember, determining the pH in soil is a science not a roll of the dice.