The Basics (& Acids) of pH

What is pH?

The pH scale measures how acidic or alkaline a substance is. 

Acidic and alkaline (or "basic") are two extremes that describe substances, and a substance that is neither acidic nor alkaline is neutral.

The pH scale ranges from 0 to 14. A pH less than 7 is acidic, a pH greater than 7 is basic, and substances with a pH of 7 are neutral.

What do the numbers mean?

Each pH value is ten times stronger than the next value. For example, a pH of 3 is ten times more acidic than a pH of 4. A pH of 11 is ten times more alkaline (or "basic") than a pH of 10.

Examples of pH in everyday household items:

pH 2: lemon juice

pH 5: black coffee

pH 7: "pure" water

pH 9: toothpaste

pH 13: bleach

Why is pH important in your garden?

Soil pH levels impact the availability and uptake of mineral nutrients. When your pH is in the proper range, the plants can thrive and uptake the nutrients they need to develop.

What soil pH do our offerings perform best in?

Strawberries: 6.5–6.8

Raspberries: 6.5–6.8

Blackberries: 6.5–6.8

Horseradish: 6.2–6.7

Currants: 6.0–6.5

Gooseberries: 6.0–6.5

Elderberries: 6.0–6.8

Rhubarb: 6.0–6.8

Blueberries: 4.5–4.8

Asparagus: 7.2 or higher 

Note: Asparagus and blueberries have very specific pH needs! Ensure you have the proper soil pH range before planting these crops. 

We recommend testing your soil in the fall to evaluate nutritional levels, pH, and Cation Exchange Capacity (CEC).

What is Cation Exchange Capacity (CEC)?

CEC is essential as it will measure the ability of soil to absorb calcium (Ca), potassium (K), and magnesium (Mg) ions (among others) and its resistance to change in pH in response to liming and sulfur additions.

The chart below outlines nutrients essential for plant growth and how their availability is affected by soil pH. 

Clays and soils high in organic matter have a high CEC, whereas sands have a low CEC. Silt loam and clay loam soils have more difficulty impacting pH due to soil structure and particle size.