How to Make Soil More Alkaline

Add lime to increase soil alkalinity.

Soil is classified as either alkaline, acidic or neutral based on the pH number it has. Alkaline soils typically have a soil pH of higher than 7. Determining whether soil is alkaline or acidic is necessary to determine which plants to place there. If you place an alkaline loving plant into acidic soil, it will fail to thrive or produce fruit. If you currently have acidic soil and want to make it more alkaline, you can add soil supplements.

Things You'll Need

• Soil test kit Distilled water Lime Tiller

Instructions

Test the Current Soil pH

1. Purchase a soil test kit from a home improvement store or garden center and locate the tube that is used to test the pH level. There are typically three to four vials in each kit that each tests different soil components.

2. Dig up 1 tsp. of soil and place it into the tube. Insert the pH test powder from the test kit into the tube and fill the tube with distilled water up to the designated water line. Place the cap on the tube and shake it up.

3. Set the tube down and allow the soil and water to settle for the amount of time instructed on the packaging.

4. Compare the color of the water inside the tube with the color chart on the kit packaging to determine how acidic the soil is. If the pH is less than 7.0, you should proceed to increase the alkalinity.

Add Lime to Increase Alkalinity

1. Determine what type of soil you have by examining it closely. If the soil dries out easily and feels dusty, it is sandy. If the soil is tightly compacted like mud, it is clay. If the soil is in a shady location with a lot of tiny plant roots in it, it is peat. If the soil is a combination of all of the above materials, it is considered loamy soil.

2. Spread a layer of lime on top of the soil in the following proportions depending on the type of soil that is present in the area. For peat soils add 25 oz. of lime; sandy soil add 4 oz. of lime; loam soil add 8 oz. of lime and clay soil add 12 oz. of lime

3. Set the blade depth of a garden tiller to 3 to 4 inches and turn it on. Move the tiller across the soil area to mix the lime into the soil.

Tips & Warnings

• The above procedure will raise the pH of the soil by 1 point.

References

• The Garden Helper: How to Test and Adjust your Soil pH
• Plantea: Acid or Alkaline? What pH Means in Gardenspeak
• Purdue University Consumer Horticulture: What is Loam?