Gardening experts are always telling people to test their soil’s pH levels. What does this mean, though? pH is simply a measure of soil’s acidity or alkalinity. Nothing more. Nothing less. This still leaves many questions unanswered. Namely, why is pH important?
What Does Acidity And Alkalinity Tell Me?
The acidity or alkalinity of soil tells you how well it can distribute nutrients. Plants obviously need nutrients like boron, nitrogen, phosphorus and iron to survive. If soil is too acidic or alkaline, many nutrients won’t dissolve properly. This prevents them from being absorbed by plants.
How Do pH Measurements Work?
The pH scale runs from 0 to 14, with values below 7 pointing to acidity and values above 7 pointing to alkalinity. Most fruit and vegetable plants can tolerate a wide pH level between 5 and 7. The best pH level is between 6 and 7, as this range covers the most number of plants and microorganisms.
Nutrients like potassium, phosphorus and nitrogen drop in availability when in soil that contains a pH level below 6.0. Likewise, nutrients like phosphorus, manganese and iron drop in availability when in soil with a pH level above 7.5.
What Affects pH Levels?
One of the biggest factors that affects pH levels is environment. Such things like quantity of rainfall and average temperature can cause pH levels to change.
Parts of the country with heavy rainfall and lots of forestation (Oregon, Washington, etc.) tend to contain more acidic soil. By the same token, parts of the country with light rainfall and limited vegetation (Indiana, Michigan) usually possess neutral soil. Last up are those areas of the country like Colorado that experience a lot of drought. They tend to have more alkaline soil.
Can pH Levels Be Changed?
Thankfully, pH levels can be adjusted. For instance, you can up the pH level of soil by adding limestone to it. However, the quantity of limestone you need to add depends on the type of soil in your garden.
- Sand: .5 Tons Per Acre
- Loam: 1.2 Tons Per Acre
- Silt: 1.5 Tons Per Acre
- Clay: 1.5 Tons Per Acre
Keep in mind that the above numbers only apply when adjusting pH from 4.5 to 5.5. To determine the amount of limestone needed for other pH levels, you’ll need to use a calculator.
pH levels can also be reduced. This tends to be easier, as there are more options available. A select few fertilizers like ammonium nitrate, urea and ammonium sulfate can lower pH levels. Some organic matter like peat moss and pine needles can also do it, though it takes years for the process to complete.
The only way to quickly lower pH levels is through the addition of sulfur.
- Sand: .2 – 1.0 Tons Per Acre
- Clay: .4 – 1.3 Tons Per Acre
Again, for more precise calculations, you’ll need a calculator.
So Why Do I Need To Test For pH?
You cannot adjust your garden if you don’t know its pH levels. This is why testing soil is one of the first (and most important) steps in the gardening process. Only after you gain a full understanding of your garden’s soils can you proceed with the actions required to make it a better garden.
The good news is that testing soil’s pH levels is very easy. You can buy a kit at any home improvement store. Better yet, you can take a sample and mail it to a laboratory. It’ll cost you some money, but it’ll also make the difference whether or not your garden becomes fruitful or not.