What is pH and How Does It Affect My Plants?

AJ & Rebecca    How To

 

Have you ever wondered what “pH” means? What those two letters stand for? Or why the abbreviation is always written with a lowercase letter “p” and the capital letter “H”? Well, wonder no more!

pH is the abbreviated way to write “potential hydrogen”. This refers to a plant or other material’s ability to attract hydrogen ions. A more simplified way to explain this might be to say that pH tells us how acidic or how basic the material is.

pH or “potential hydrogen” or “acidity/alkaline balance” is measured using a number on a scale from 0 to 14. Zero represents a material with the highest possible concentration of acid, whereas 14 represents a material with the highest possible alkalinity. Seven is considered neutral, or a balance of acidity and alkalinity.

Generally speaking, most plants prefer a growing environment with a neutral pH. However, some plants do prefer a touch more acidity over alkalinity in order to flourish. Other vegetation may prefer slightly more alkaline conditions in order to produce blooms with the most desirable colors or flavors. These instructions can always be found on your seed packets or from wherever you purchase your transplants.

One of the keys to happy plants is ensuring that you maintain an ideal pH balance in your soil, as well as the water that you are using to nourish your plants. Most sink tap water lands in between the range of 7.0 and 8.5. However, have no fear, there are ways to lower the alkalinity of your water, as well as methods to use to test your water to confirm the pH prior to use.

How To Test Your Soil’s pH

Probably the most well-known way to test soil or water pH is to send a sample off to your local county’s testing office or to purchase a packet of pH testing strips for home use. While either of these methods is effective, sending off a sample is not very time-efficient, and testing strips can become quite costly. In any event, here on the farm, we like to do things “DIY” whenever possible. So, we will share our favorite pH testing methods with you. If you choose to send off your samples or use testing strips instead, just know those are perfectly fine methods as well.

Testing Soil or Water pH at Home (The DIY Method)

First, the soil test:

  1. Collect one cup of soil from your garden.
  2. Put two spoonfuls of the soil into two separate containers.
  3. Add one-half-cup of vinegar to one of the containers with the soil. If the soil fizzes, it is alkaline with a pH between 7.0 and 8.0.
  4. If the first container does not fizz, add one-half-cup water to the other container, and mix well with soil. Once mixed, add in two tablespoons of baking soda. If the soil fizzes, it is acidic with a pH between 5.0 and 6.0.
  5. If your soil does not react with either the vinegar or the water, it is neutral.

Next, the water test:

  1. Cut up one cup of red cabbage. Place cut cabbage into a blender.
  2. Add 500 mL of boiling water directly to blender.
  3. Blend to draw out anthocyanins, the chemicals found in reddish-purple plants that will change color when exposed to an acid. (This can also be done with other reddish-purple plants such as dark berries or roses.)
  4. Blend until water is dark purple, then allow to sit for ten minutes.
  5. Pour the mixture through a fine mesh strainer or coffee filter to remove any non-liquid pieces. Discard these pieces and save remaining liquid. This liquid is your “indicator solution”.
  6. Add 50mL of isopropyl alcohol to your indicator solution to prevent bacterial growth. If the alcohol changes the color of the solution, add small amounts of white vinegar until it is once again dark purple.
  7. Soak plain paper fully in indicator solution and then allow to dry overnight on a towel. Using gloves is a good idea for this step, as the solution will stain.
  8. Cut the dried paper into test strips.
  9. Use the strips to test water or any other liquid. Simply submerge paper in water and if it turns pink, it is acidic. If the paper turns blue or green, it is alkaline.

One of the recommended ways to improve acidic soil is to add lime. But, you want to remember that any such changes must be done several weeks prior to planting in order to give the minerals time to decompose and for any desired changes to take effect. Along the same lines, gypsum can be added to overly alkaline soil to help increase the acidity for any plants that would benefit from such a change.

Obtaining the Perfect pH in Your Water

Ensuring that we are watering our plants with water that is the proper acidity is one of the more-important but often-overlooked steps of home gardening. A primary recommendation for controlling your water’s pH is to invest in a large reservoir for holding your garden water, like a 180-gallon rain collection unit, for instance. This will allow you to not only recycle rainwater which is excellent for the environment and local ecology but also give you the ability to treat the water to your garden’s specifications prior to use.

One way of doing so is to treat your water with natural, fresh-squeezed lemon juice. Alternatively, if you are using a reservoir, you can place an aeration system in it to increase the pH levels in your water. While there are store bought bottles to aid in lowering and raising pH levels, we’re not a big fan of using them.

Once you lower your water from the tap-average 7.0-8.5 to a more desirable 6.3-6.8, you are ready to water your garden!

Checking Your pH Levels

Ensuring a correct pH in your garden will aid in a few different ways. First, it will allow you to better diagnose nutrient deficiencies or toxicities occurring within your garden, or within a specific plant. In addition, keeping proper pH levels in your garden will ensure adequate growth and delicious fruit and vegetables to enjoy!

While you may not always be able to ensure a perfect pH in your garden through using our Do-It-Yourself methods, by checking the pH regularly you will certainly be able to better maintain and treat your garden with what it truly needs. This is more critical than many new home gardeners realize. But, why? Well, because as pH shifts, certain vital chemicals can become “locked out” or overloaded. More specifically, the plant may not be able to absorb the appropriate amounts of hydrogen from the soil, due to imbalanced pH.

In addition to hydrogen ions, in very alkaline soil certain micronutrients such as zinc and copper become chemically unavailable to plants. On the other hand in very acidic soil, macronutrients such as calcium, magnesium, and phosphorus are not absorbed while others may reach toxic levels.

We hope that by sharing this information we’ve helped show you the importance of maintaining a balanced pH among all of your plants, as well as shared some tips for making this easier to do from home. As always, if you have any questions, do not hesitate to let us know!

One response to “What is pH and How Does It Affect My Plants?”

  1. How to Add Lime to Acidic Soil says:

    […] remember that nearly all grass varieties will grow well if the soil pH ranges from 5.5 to 7.5. If your soil pH is much lower than even 5.5, you need to apply […]

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