Correcting Soil Acidity (and Why It’s Important!)
Correcting soil acidity is an essential part of gardening, because just like animals, plants need the right conditions to not only survive but thrive. While you could potentially be doing everything else right in your garden, if your soil acidity is off, you’re going to be fighting a bit of a losing battle. Every plant has a preferred level of soil acidity, so it is something of which every gardener should have a basic knowledge and understanding.
How Does Acidity Affect Soil?
Before we answer this question, it is probably worth explaining what acidic soil is and how it is measured. Acidity and alkalinity of soil (and any other substance, really) is measured on the pH scale, which runs from 0 to 14, with 7 being neutral.
From neutral, things get more acidic as you count down toward zero, and more alkaline as you go up from 7. Plants have different soil requirements, and while most prefer pretty neutral soil when it comes to the pH level (around 6.2 to 7), there are definitely some exceptions to be aware of.
Now, back to that first question—how does acidity affect soil? Well, if your plants are living in soil that is too acidic or too alkaline, they won’t be able to absorb nutrients properly, which can make it pretty challenging to grow a healthy, beautiful garden. You can water and fertilize all you want, but if your plants seem pretty stressed out, chances are the pH in your soil is off.
What Happens If Soil Is Too Acidic?
Remember, soils with less than a 7 on the pH scale are generally considered acidic, and while having somewhat acidic soil can be good, that is not always the case. Heavily acidic soils can cause plants to become deficient in nutrients like phosphorus, magnesium, and calcium and are often referred to as ‘sour.’
Deficiencies caused by soil acidity will make themselves known by plants in a few different ways. A phosphorus deficiency, for example, can cause lanky, stunted growth, and dull, dark leaves. On the other hand, a magnesium deficiency will often present in a sort of marbled yellowing of leaves.
What Causes Soil Acidity?
There are a few different reasons for soil to become acidic or sour. It happens underground where there is organic matter breakdown and is common in locations where chemical fertilizers are used. Excessive rainfall can also, in time, leach soil of elements like calcium, magnesium, potassium, and sodium, which prevent soil acidity. These deficiencies transfer directly to your plant babies if they require more neutral or alkaline soil levels.
How Do You Correct Soil Acidity?
The first step to take when it comes to correcting a soil problem is determining how big of a problem it really is. In order to do this, you will want to conduct a soil test. You can test your soil with a DIY kit at home and go from there. You will want to do this once every few years as these levels are likely to fluctuate.
Correcting soil acidity can take time and isn’t a one-off job. While you won’t need to correct all of your soil (just wherever you are growing plants that require a different pH level), you will need to do it on a bit of a regular basis to keep it there.
You can raise the pH of acidic soil by ‘liming’ it. The most common, economical, and generally easiest way to do this is by adding limestone. Made up of either calcium carbonate or calcium and magnesium carbonate, it will help to neutralize the acid in the soil. How much you add will depend on the current pH level of your soil.
Limestone is not water-soluble, so you can either mix it into the top six inches of soil (in a pinch), or, if you include a soil test in an annual fall clean-up plan, simply lay it on top of the ground, and it will eventually work its way through on its own. Alternatively, if you are hoping to lower the pH because your soil has too much alkalinity, apply a fertilizer that has sulphur in it rather than lime.
What if You Have Naturally Acidic Soil?
If you have naturally acidic soil, then you might consider selecting plants that do well in that environment. Azaleas, rhododendrons, daffodils, hydrangeas, blueberries, and even strawberries are all considered acid-loving plants.
Now that you’re basically a soil scientist, stop by our garden centre in Powell River to put your newfound knowledge into action. We’ve got everything you need to get your soil where it needs to be and the right plants to go along with it.