How to Balance pH for Liatris Plants

Maintaining the proper soil pH is crucial for the healthy growth and thriving of Liatris plants. Liatris, also known as Blazing Star, prefer an acidic soil with a pH range of less than 6.8. To ensure your Liatris plants receive the optimal growing conditions, it’s essential to understand the process of balancing the soil pH.

Determining the Current Soil pH

The first step in balancing the pH for Liatris is to determine the current pH level of your soil. You can use a soil test kit, which typically includes a probe or test strip that changes color when inserted into the soil. The color corresponds to a specific pH value, which you can then compare to the desired range for Liatris.

Lowering the Soil pH

liatrisImage source: Pixabay

If the soil pH is too high, meaning it’s more alkaline, you’ll need to lower it to create the acidic conditions that Liatris thrive in. This can be achieved by adding elemental sulfur or a sulfur-containing fertilizer to the soil.

Elemental Sulfur

Elemental sulfur is a common and effective way to lower soil pH. The amount of sulfur needed will depend on the current pH level and the soil type. As a general guideline, if the soil pH is 7.5 and needs to be lowered to 6.5, you may need to apply approximately 1 pound of elemental sulfur per 100 square feet of soil.

To apply the sulfur, you can broadcast it evenly over the soil surface and then incorporate it into the top 6 inches of soil using a rototiller or garden fork. Alternatively, you can apply it in bands along the rows of Liatris, about 2 inches deep and 6 inches away from the plants.

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Sulfur-Containing Fertilizers

Another option for lowering the soil pH is to use a sulfur-containing fertilizer. These fertilizers release sulfur as they break down, gradually lowering the pH over time. Examples of sulfur-containing fertilizers include ammonium sulfate, superphosphate, and sulfate of potash.

When using a sulfur-containing fertilizer, follow the application instructions on the product label, as the recommended rates may vary depending on the specific formulation.

Monitoring and Adjusting the pH

After applying the sulfur or sulfur-containing fertilizer, it’s essential to retest the soil pH after 30 to 60 days to monitor the changes. If the pH is still too high, you may need to apply additional sulfur or adjust the application rate.

It’s important to note that the soil pH adjustment process can take some time, as the sulfur needs to react with the soil to lower the pH. Be patient and continue to monitor the soil pH until the desired range is achieved.

Maintaining the Optimal pH

liatris 2Image source: Pixabay

Once you’ve achieved the desired pH range of less than 6.8 for your Liatris plants, it’s essential to maintain it. This may require periodic soil testing and additional applications of sulfur or lime (if the pH becomes too low) to keep the soil in the optimal range.

Additional Care for Liatris

In addition to balancing the soil pH, Liatris plants also have other specific care requirements:

  • Consistent Moisture: Liatris prefer consistent moisture, but overwatering can lead to rotting of the corms. Aim for consistent, even moisture, but avoid waterlogging the soil.
  • Moderate Fertility: Liatris have a moderate fertility requirement. Feed them with a balanced fertilizer at a rate of 100-150 ppm N with every watering. Avoid over-fertilizing, as this can lead to weak flower spikes.
  • Planting Depth: Plant bare root corms with the top right at the soil surface, just barely covered with soil.
  • Temperature: The soil temperature should be below 70°F when applying sulfur or other pH-adjusting amendments.
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By following these guidelines and maintaining the optimal soil pH, you can ensure your Liatris plants thrive and produce their stunning, vibrant flower spikes.


  1. Soil pH and Plant Growth – Penn State Extension
  2. How to Adjust Soil pH – Gardening Know How
  3. Soil Testing and pH Adjustment – The Old Farmer’s Almanac