How to Balance pH for Trumpet Flower Plants

Maintaining the proper pH level is crucial for the healthy growth and vibrant blooms of trumpet flower (Brugmansia) plants. This guide will provide you with a comprehensive understanding of balancing the pH for your trumpet flower, including the ideal soil pH range, methods to adjust the pH, and ongoing care tips to keep your plants thriving.

Ideal Soil pH Range for Trumpet Flowers

Trumpet flowers thrive in slightly acidic soil with a pH range between 5.5 to 6.5. This pH range ensures the optimal availability of essential nutrients for the plant’s growth and development.

Assessing Soil pH

trumpet flowerImage source: Pixabay

To determine the current pH level of your soil, you can use a soil test kit or take a sample to a local cooperative extension office for analysis. This will provide you with the exact pH reading and guide you on the necessary adjustments.

Adjusting Soil pH

If your soil pH is outside the ideal range for trumpet flowers, you can take the following steps to balance it:

Increasing Soil Acidity (Lower pH)

If your soil is too alkaline (pH above 6.5), you can lower the pH by incorporating the following amendments:

  1. Sulfur: Apply elemental sulfur to the soil at a rate of 1-2 pounds per 100 square feet. Sulfur will gradually lower the pH over several weeks.
  2. Aluminum Sulfate: Mix in aluminum sulfate at a rate of 1-2 pounds per 100 square feet. This will quickly lower the pH, but the effects may be short-lived.
  3. Peat Moss: Incorporate peat moss into the soil at a rate of 2-4 inches per square foot. Peat moss is naturally acidic and will help lower the pH over time.
See also  How to Balance pH for Wild Petunia

Increasing Soil Alkalinity (Raise pH)

If your soil is too acidic (pH below 5.5), you can raise the pH by adding the following amendments:

  1. Lime: Apply ground limestone (calcium carbonate) to the soil at a rate of 2-4 pounds per 100 square feet. Lime will gradually increase the pH over several weeks.
  2. Wood Ash: Mix in a small amount of wood ash, about 1 cup per 100 square feet, to raise the pH.
  3. Dolomitic Lime: This type of lime contains both calcium and magnesium, which can help neutralize acidity more effectively than regular limestone.

Ongoing Care and Maintenance

trumpet flower 2Image source: Pixabay

To maintain the ideal pH for your trumpet flowers, consider the following tips:

  1. Frequent Soil Testing: Test the soil pH regularly, at least once a year, to ensure it remains within the optimal range.
  2. Adjusting Fertilizers: Use a balanced, water-soluble fertilizer formulated for acid-loving plants. Avoid fertilizers high in nitrogen, as they can lower the soil pH over time.
  3. Monitoring Watering: Ensure the soil is consistently moist but not waterlogged, as excessive moisture can affect the soil pH.
  4. Mulching: Apply a 2-3 inch layer of organic mulch, such as bark or wood chips, around the base of the plant. This will help retain moisture and prevent soil pH fluctuations.

By following these guidelines, you can effectively balance the pH for your trumpet flower plants, ensuring their optimal growth, vibrant blooms, and overall health.


  1. The Spruce: Angel’s Trumpet (Brugmansia)
  2. University of Wisconsin-Madison: Angel’s Trumpet (Brugmansia)
  3. Living Color Garden Center: How to Care for Angel’s Trumpet Plant
See also  How to Balance pH for Epimedium: A Comprehensive Guide