How to Test Soil pH
To check the pH of your soil, you can do a full-scale soil test through our local site, take an agronomics consultation or a slimmed-down version with a do-it-yourself pH test kit from a nursery or garden center. If you test the soil frequently, consider purchasing a pH meter.
Important: Be careful when making any changes or adding anything to your soil, as incorrect adjustments may lead to unintended consequences for your plants and garden.
Here are soil amendments to increase the soil pH before planting:
Agricultural Lime
Agricultural lime, called aglime, is the same as garden lime or limestone. It is calcitic lime, the most commonly used material to make soils less acidic, Limestone is available in pulverized, granular, pelletized, and hydrated forms. The finer the particles, the faster the lime changes the pH of the soil so pulverized lime works the fastest but it also has the drawback of clogging, which occurs less with granular and pelletized lime.
Lime needs to be thoroughly worked into the soil with water to react.
As for the amount, it depends on the current and the target pH of the soil, as well as the texture of the soil. Soils high in organic matter and low in clay require less lime than heavy clay soils to obtain the same pH increase.
Dolomitic Lime
Unlike calcitic lime, which contains only calcium, dolomitic lime also contains much higher magnesium levels, a micronutrient. It is used when the soil also lacks magnesium. In their ability to neutralize soil acidity, the two materials don’t differ.5 Dolomitic lime is usually sold in pelletized form.
Tip
While eggshells are a suitable alternative to garden lime, they need to be finely ground and impractical for home gardeners to do (crushing them by hand is insufficient). Ground eggshells also have a slower dissolution rate than agricultural lime so you will not see any quick results in your soil pH.6 Egg shells are, nonetheless, an excellent addition to the compost pile.
Wood Ash
Wood ash from a fireplace or a wood-burning stove contains a high amount of calcium which makes it similar to agricultural lime. However, wood ash should only be used if the soil pH is below 6.5. In soil with a pH above 6.5, adding wood ashes would make the soil too alkaline. Like all amendments that change the soil pH, do not add wood ash without testing the soil pH beforehand.7
Tip
Baking soda is often touted as an easy, low-cost, and fast way to increase soil pH. However, it is a salt (sodium bicarbonate) and not formulated for agricultural use. Upon contact with water, it makes a solution alkaline and neutralizes acidity, but it is only a quick fix that risks burning plants.