Soil-PH

What is soil pH?

Soil pH refers to the acidity / alkalinity of the soil. Logarithmic scale from 0-14 (7 is neutral) that indicates the hydrogen ion concentration in the soil solution (water in the soil). 

Low pH is more acidic.

High pH is more basic.

How to measure pH?

• Standard soil test by a soils lab (when you're already sending something to the lab for other purposes)
• Meter (relatively inexpensive at ~$100). Can sample the soil at various places quickly and easily.
• Colormetric kits (Cheap but takes more time to do)

Significance

Many plants are very sensitive to soil pH and are unable to extract certain nutrients from soils if the pH is too low or too high. A shift from 7 to 6 is drastic!!!

• High pH's result in some nutrients/metals being bound tightly to soil particles.

• Low pH's result in higher heavy metals being more available for uptake.

It's important to know the pH of the soil so that appropriate planting decisions can be made.

 

Soils in Vancouver

Vancouver soils tend to have a low pH. Granitic stone and gravel is often used in construction, meaning that soil pH is rarely too high.

In regions where there is limestone bedrock or where limestone is used in construction, soil pH's above 7.5 or 8 are common in urban areas.

 

Changing pH

Elemental Sulphur lowers pH level by Sulfur bacterium.

Wood Ash raises pH level by mixing with soil water to form lye.

NOTE: It's very difficult to lower soil pH in a real-world setting.