How to Lower the PH Level of High Alkaline Soil. The pH level of soil ranges on a scale from 1 to 14. The middle of the scale is considered neutral, and the higher the number is on the scale, the higher the alkaline content in the soil. Plants require different alkaline levels in the soil, and sometimes the soil needs to be adjusted to suit the plant that will go into a specific area. Here are some helpful tips for lowering the pH level of high alkaline garden soil.
Determine the plants, flowers or vegetables that will be planted into your garden. Some plants prefer a higher alkaline content in soil, and others thrive with a lower pH level making it more acidic.
Take a soil sample in the area where you wish to plant. You may take your sample to a local garden center, or purchase a soil testing kit from the center.
Review the results of your soil sample. Once you've determined the alkaline content of the soil, you can make adjustments.
If you have a sandy soil, you will need to add 1.2 ounces of ground rock sulfur per square yard. This will lower your pH level by 1.0 on the scale.
You will need to add 3.6 ounces of ground rock sulfur per square yard for other types of soil. This too will lower your pH level by 1.0 on the scale.
Add sawdust, compost and peat moss as other options to lower the soil's pH level.
- Dig at least 6 to 8 inches deep for a soil sample or the depth you will plant flowers and vegetables.
- Read the labels on the soil testing kits carefully.
- Read all labels carefully, and follow the manufacturer's directions when applying any type of chemical to your garden.
- It is sometimes easier to make soils more alkaline than more acidic.
- Sulfur is not always easy to find or available. If you are using other materials than sulfur, you will need to adjust and retest the soil over time.
- Wear protective gloves and masks when applying chemicals to your garden.
- If the soil is extremely high in alkalinity, you may need to build a raised bed and use a high quality topsoil.