Understanding Soil pH

If you are new to gardening you might not understand the importance of soil pH levels in your soil. While it is still something I am learning about, I thought I would do some research and write a blog on it to also help with my understanding of the subject.

So first off, what is soil pH and why does it matter?

The nutrients that plants need to survive are absorbed through their roots. The way plants receive those nutrients is by absorbing them once they are dissolved in water. If the mixture of the water with the nutrients is either too acidic or too alkaline, the nutrients won’t be able to easily dissolve and the roots will be incapable of absorbing them, making the plant unable to grow.  This is where your pH level comes in. Soil pH is the measurement of the amount acidity or alkalinity that is in a soil.  pH is measured on a scale of 0 to 14, 0 being pure Hydrochloric acid and 14 being pure sodium hydroxide, which is alkaline. No plant can survive in either of the extremes, however some plants do better in soil that is more acidic than alkaline and vice versa.  Neutral pH is 7, and most plants do best when they are in the range of anywhere between 6 and 7.5.  You can find out the pH level of your soil with a test kit that can easily be found in any gardening store, nursery or online. So, soil pH level is important because if it is off, you're plants can't absorb any nutrients and they won't survive. 

That being said, it is important to test your soil to find out if you need to adjust your soil so that your plants have the best possible chance of survival. However, be aware of what you are planting. HERE is a link to see the list of plants that thrive best in certain levels.  If your test shows that the number is more than a .5 difference from what you need, you are going to need amend your soil.

Once you find out what level your soil is at, if it is not what you need it to be, you are going to need to figure out how to adjust it.  Be aware that it can take months to adjust the pH level of your soil.  You should test every 2-3 months and only expect about a .5 unit of difference in that time. Every time you test, you can add more amendments. Also, be conscious about the fact that adding extra amendments can cause more harm than good. If you are adding anything that comes from a bag, make sure to follow the directions exactly. Too much can be damaging.  It is usually best start testing and amending in the fall time so that hopefully by spring you are ready to start planting. You will make it easier for yourself if you choose plants that thrive best in the soil you already have.

Now, to adjust your soil, lets first say your soil is acidic. This means that the pH level is lower than 7.  With acidic soil it means that your soil is lacking in calcium and magnesium. The most common organic fixer for soil with high acidity is Lime.  There are two different lime amendments. Dolomitic limestone is for if your soil has tested low in magnesium, and calcitic limestone for if your soil is low in calcium. Other things that work well for acidic soil are eggshells, oyster shells, clamshells, calcite, or hardwood ashes.  

Next, lets pretend your soil is too alkaline. This means that your pH level is above 7 and that your soil is low in iron, phosphorous, and zinc.  The best way to handle high alkaline soil is to increase the nitrogen. Things that are good to add nitrogen are sulfur, acidifying fertilizers or peat moss. Again, make sure to follow instructions on your bag. However, you can never add too much organic matter such as compost, animal manure, or worm castings. You can add any kind of organic matter on as often as you want to because it will only continue to help your soil. It is also good because it is providing food for the microorganisms that are living in your soil, and you need microorganisms because when they digest the matter, they create nutrients for your plants and help create great soil structure. Click HERE to understand in depth why microorganisms are important.

Note: Peat moss is controversial because the way it is obtained is not very sustainable. Coco coir is a good alternative however it ‘s pH is closer to neutral so for using it to try and lower levels it might not do anything.

So, once you have decided what amendments to add to your soil, all you have to do is follow the instructions on the bag and apply! Or in the case of adding organic matter, just cover your bed completely. Then till it all in and you are good to go until you need to test again. Now, many people believe in no-till farming and that is another subject but I think technically if you leave amendments on top it’s considered mulch.  This will over time amend your soil but it takes much longer to decompose.

  I hope now you have a better understanding on what soil pH is and why it is important. I encourage anyone with a garden who hasn’t tested their soil to do so and maybe it will answer some questions if you are having growing some particular things! Thanks and have a great day!