Soil pH Adjuster Calculator
Instantly calculate exactly how much garden lime or elemental sulfur you need to raise or lower your soil pH based on your specific soil type and square footage.
Calculator Tool
Soil pH Adjuster
Calculate exactly how much lime or sulfur is needed to raise or lower your soil pH.
Required Amendment
* Broadcast evenly and till into the top 6 inches of soil.
How to Adjust Soil pH
Balancing your soil's pH is the foundation of a healthy garden. If soil is too acidic (low pH), macronutrients like nitrogen and phosphorus become locked up and unavailable to plant roots. If it is too alkaline (high pH), micronutrients like iron and manganese become deficient.
Raising pH (Making Soil More Alkaline)
If your soil is acidic (e.g., pH 5.5) and you want to raise it to a neutral 6.5 for vegetables, you need to add alkaline materials. The most common and cost-effective amendment is agricultural or garden lime (calcium carbonate).
Lowering pH (Making Soil More Acidic)
If your soil is alkaline (e.g., pH 7.5) and you want to lower it to 5.5 for acid-loving plants like blueberries or azaleas, you need to apply elemental sulfur or aluminum sulfate.
Frequently Asked Questions
How much lime do I need to raise soil pH?
The amount of lime required depends on your starting pH, target pH, and importantly, your soil type. Clay soils require significantly more lime than sandy soils to achieve the same pH shift due to higher buffering capacity.
How long does it take for lime or sulfur to change pH?
Garden lime (calcium carbonate) can take 2 to 6 months to break down and fully alter the soil pH. Elemental sulfur requires soil bacteria to convert it to sulfuric acid, which can take several months depending on soil temperature and moisture.