You’ve heard this abbreviation before, “pH.” pH stands for potential Hydrogen. What does that mean? Why does it matter? And, if it’s “broke,” how do I fix it? In this article, we’ll try to grasp an understanding of soil pH and why it matters. I hope the explanations will be a bit more clear than a black rock at the bottom of a deep well at midnight. Here comes some light:
First, let’s look at the ranges:
The pH range goes from 0 which would be acidic and up to 14 which would be alkaline or basic. Battery Acid would be 0 and would “burn” you. Lye would be 14 and would “burn” you just as bad (if not worse). Blood is normally slightly basic / alkaline with a pH range of 7.35 to 7.45.
In the picture, you see lemon has a pH of 2 and stomach acid has a pH of 1. We can touch lemon juice but not stomach acid (for very long anyway). But, there is only 1 deviation between the two. The pH scale is not linear like a ruler where 2 inches is twice as long as 1 inch. The pH scale is logarithmic. We’ll keep this logarithmic thing simple. Each deviation on the pH scale is increase or decrease by a factor of 10. This mean that stomach acid is 10 times more acidic than lemon juice and 100 time more acidic than grape juice.
There are two other videos that I made on this topic that also has information about fertilizers for your soil. They are a bit longer than this video. Here are the links:
Whew. Done with complicated. Let’s talk about what this means for our gardens.
Soil acidity or alkalinity is something we should pay attention to but not loose too much sleep over. pH is important because the pH level influences how efficiently plants can take up nutrients from the soil. And “how efficiently” is specific to each variety of plant. When you are reading and researching how to grow a specific plant more efficiently, there is usually a reference to the optimal pH level that plant will thrive in. Tomatoes do best in soil with a pH around 6.0 to 6.8. If you check your specific soil’s pH and it’s 7.0, you’ll be okay. The good news for us homesteaders is that most plants will tolerate a fairly wide range of soil pH (there are exceptions).
Most all plants need most all nutrients that are found in your soil. However, specific plants need higher levels of specific nutrients than other plants. Some nutrients dissolve and become available to the plant in acidic soils and other nutrients dissolve and become available to plants in alkaline soils. Think of the small openings in the roots as the plant’s many little mouths. Chunks of calcium, iron and phosphorous can not just be “chewed and swallowed” by the plant. The nutrients have to be dissolved and become bio-available in order to be absorbed into the plant’s roots. Depending on the plant and depending on the nutrients that the specific plants needs to thrive will determine the best pH conditions for that plant.
pH 5.5 – 6.0 – Bean, Brussels Sprouts, Carrot, Peanuts, Rhubarb, Soybean
pH 6.0 – 6.5 – Broccoli, Cabbage, Cannabis, Cauliflower, Cucumber, Pea, Sweet Corn, Pumpkin, Squash, Tomato, Turnip
pH 6.5 – 7.0 – Asparagus, Beet, Celery, Lettuce, Melons, Onion, Parsnip, Spinach
You will find some plants need more acidic soils and attention to detail is necessary for these plants to thrive. If you are shooting for a sweet soil pH of 5.5-7.5 for your entire garden, you may do well…for the most part. You may start scratching your head as to why your blueberries appear to be suffering.
pH 4.5-5.0 Blueberry, Cranberry
pH 5.0 – 5.5 Parsley, Potato, Sweet Potato, Radish
The video links above will help a little bit in the “how do I fix my soil’s pH level.” Nonetheless, we’ll touch on it just a bit.
Take vinegar and baking soda and mix them together. Yep, lots of bubbles and stuff. This is a reaction between the acidic vinegar and the alkaline soda to form a new pH (depending on how much of each solution you mixed together). The process is similar with adjusting the soil…and how much solution you add to your soil does need a careful eye.
If your soil is a bit too low on the pH scale (acid), adding an alkaline material is necessary. This process is called called liming and limestone is the substance commonly used to make this adjustment (easy to remember).
In the fall, you could apply the limestone to allow the pH to change somewhat by the spring’s growing season. You may find that if your soil type is clay, you may need more of the limestone than you would if your soil type is sandy.
Soils that are higher on the pH scale will need the addition of acidic solution. Most of the time you will find that lowering your soil’s pH is best done with powdered elemental sulfur. Follow the directions on the packaging and keep in mind that your soil’s type may influence how much elemental sulfur you will need to add.
We are homesteaders living in a modern society. Let’s take advantage of the resources that are still available. If you believe your soil’s pH needs adjusting, you could gather samples from different sites in your garden, take the sample to a trusted laboratory for analysis and follow the laboratory’s recommendations.
Here’s a link to a PDF from Texas A&M on how to collect a soil sample for analysis. The laboratory you have access to may have different collection requirements, but this PDF may give you a good idea of how to collect samples. If the link does not work, send me an email and I will email a copy of the PDF to you.
Here’s a link to your local county, parish, borough offices:
How much? Each product has specific instructions. And, if you take a sample into a laboratory and get recommendations, you’ll really want to take note of those recommendations. Remember, fertilizers, limestone and elemental sulfur are not like money…more is not necessarily better. You may fill the “bank” but still end up “bankrupt.”
When you test your soil or have your soil tested, you will likely find the result to be between a pH of 5.0-8.0 with some of your soils being between pH 4.0-9.0. You want to shoot for the pH range of 5.5-7.5 and increase or decrease the pH for specific plants with “picky” pH needs. Create a blueberry bed and work at achieving a soil pH of between 4.5-5.0. This kind of adjusting is good garden practice. However, if you are testing your garden beds and rows and trying to adjust each for the specific plants you’ll be growing in each bed or row, you’ll end up pulling all your hair out…and hair has a pH range between 4.5-5.5 and that may mess up your soil’s pH level even worse and then what will you pull out?