What’s a pH?

Soil pH influences plant growth and can make our break a garden.  My intention is to highlight what I believe is of the greatest practical importance to the home gardener.

The pH of your garden’s soil is a numerical value which indicates its potential hydrogen ion concentration.  For garden soils, the typical range in values might be between pH 5.0 (more acidic) to 8.5 (more basic).  As you’ll recall, a pH 7 is neutral and this is typically the value for drinking water.

The soil’s pH is something every gardener should know before planting a garden.  The reason being that many soil nutrients (e.g., nitrogen, phosphorous, magnesium, etc.) are more readily available to plants in the range of pH 5.8 – pH 7.5.  In other words, if your soil’s pH is below 5.5 or higher than 7.8, the availability of plant nutrients decreases. Hence, nutrients become less soluble and/or bound to the soil media. Of course, this is a generalization since each nutrient behaves somewhat differently in relation to pH.

If you are about to establish a garden in new (unknown) ground, it will behoove you to have a soil test conducted before you do anything else.  You can typically do this via a county extension agent, a local (private) environmental laboratory or a university soil testing laboratory.  Fortunately, for Boone County (MO) gardeners, we have access to two laboratories who provide excellent testing services. I’ve listed these below.

The first reference is for a private lab located in Fayette, MO. This is a pleasant drive from Columbia and their company name is Inovatia Laboratories, LLC.

Inovatia Laboratories, LLC

The second reference is for the Soil and Plant Testing Laboratory located on the University of Missouri’s Columbia campus.

  • 1100 University Avenue
  • Mumford Hall – Room 23
  • Columbia, MO 65211
  • Phone: 573-882-0623
  • Fax: 573-884-4288

In summary, by knowing your soil’s pH and its nutrient profile, you’ll be able to successfully amend your soil so that it’ll be more suitable for the growth of fruit and vegetables. For more information, please visit my post on pH and Amendments.


Soil Blending

Hi! Johnny L. Dose here again, aka John Allan. Now that I know how to contribute to The Garden Dreamer, I would like to switch gears to the topic of soil blending from the last topic of vermiculture, which we will definitely come back to.

I blend my own soil. Why? Well, first the growth media for plants has just as much importance as keeping your plants watered, your plants with the right type and amount of sun, and with selection of seed genetics that you choose for you plants. Soil Fertility is the collegiate term for this expertise. And as a science, it’s as old as dirt. 🤣

The ingredients that I use currently are:

  • Local topsoil
  • Sand or Clay (optional depending on your local topsoil’s texture)
  • Peet Moss
  • Vermiculite
  • Perlite
  • Wood Ash from the fire pit
  • Re-hydrated oyster shells after burning (after planting)
  • Worm castings (after planting)
  • Osmocote pellets

How you blend these ingredients is up to you. I’ll tell you how I do it.
My unit of measure, which I totally made up, is The Smokey the Bear Shovel load; [unit = “sb”]

In a wheelbarrow, (Mfg: True Temper), add: 7sb of local topsoil, 5sb peat moss, 3sb vermiculite, 3sb perlite, 2sb wood ash. I usually put on some blue hospital gloves partly to freak out the cats, but also to blend ingredients by hand or you can use the shovel.
Note:  Chicks don’t like dirty fingernails.

As you are mixing include osmocote pellets. Don’t go overboard. Treat it like adding pepper to a pot of soup or a garden salad.

The addition of sand or clay is an important topic, which can be in the next contribution. If you look up soil texture and if the link above actually works, you’ll find that texture, what we know as combinations of sand, silt, and clay, is all based on particle size. The various other names for soil, such as: loamy sand, sandy loam, loam, silt loam, silty clay, silty clay loam, sandy clay loam, clay loam, and sand clay make up all the defined USDA textures; aka the texture triangle.

“Light” soils are sandy soils (course texture; large particle; easy to plow)
“Heavy” soils are clayey soils (fine texture; smallest particles; hard to plow)
Note: I guess they were thinking about the plow horse when they came up with those terms:

Good Textbook: “The Nature and Properties of Soils”, Nyle C. Brady, 8th ed. (1974).

Anyway, feel free to ask me any questions about my experiences with soil blending. I’ll stop now and save some material for my next post.

All the Best,

Johnny L. Dose

TGD 01/01/2022

pH and Soil Amendments

Now that you’ve read my post on “What’s a pH?”, you may want to know what can be done to either lower or increase your soil’s pH.  Of course, the first thing you need to do is have a reputable university or private laboratory test your soil.    Once you have the lab results, you’ll know if pH needs to move up (more basic) or down (more acidic).

In all my years of gardening, I can safely say that the vast majority of garden soils that I’ve encountered were either too acidic (pH 4.6 – 5.5) or already in a suitable range for plant growth (pH 6.2 – pH 7.2).  However, it’s always possible to encounter a soil with a high pH (pH 7.6 – 8.8) as well.

By no means, will the following suffice to fully explain the dynamics relative to soil pH/soil chemistry/soil type and amendments.  There are complete texts devoted to these topics and some knowledge of basic chemistry is needed to weed through the facts. Hence, the following should be seen as a guide to amend your soil, if deemed necessary.

Should your soil test result in an acidic reading (pH 4.5 to 5.5), it is likely that the test results will offer guidance on the quantity of gypsum (CaCO3) to apply.  This is an easy task and product (CaCO3 / lime) can be purchased at a big box store.  As to knowing how much CaCO3 to apply to your garden, this depends on the soil texture, the soil’s pH level and the target pH you’re hoping to establish.

In the event that your soil’s pH is basic (pH 7.5 – 8.5), the means to lower pH is not as straight forward.  However, the use of fertilizers designed to benefit acid loving plants is one way to temporarily offset the effects of high pH.  Additionally, adding large amounts of compost to your garden will also lower your soils pH, but slowly.  A third factor involves incorporating green manure crops in your garden plot.  Although not considered as an “organic” amendment, fertilizing with Ammonium Sulfate helps to lower soil pH while also adding nitrogen to your garden.

Please, don’t be shy to reach out with any questions or comments regarding this post.  Managing your soil so that its pH is in a suitable range (6.2 – 7.2) for optimum plant growth and development is every gardener’s goal!