How to Balance pH for Phacelia Tanacetifolia

Maintaining the proper pH level is crucial for the healthy growth and development of Phacelia Tanacetifolia, a versatile and beautiful wildflower. This comprehensive guide will walk you through the steps to balance the pH for your Phacelia Tanacetifolia plants, ensuring they thrive in your garden.

Ideal pH Range for Phacelia Tanacetifolia

Phacelia Tanacetifolia, also known as Lacy Phacelia or Tansy Phacelia, prefers a soil pH range of 6.1 to 7.8. This slightly acidic to neutral pH range provides the optimal conditions for the plant to absorb essential nutrients and flourish.

Determining Your Soil’s pH

phacelia tanacetifoliaImage source: Pixabay

To determine the current pH level of your soil, you can perform a simple soil test. This can be done using a soil testing kit, which you can purchase from a garden center or online. Follow the instructions provided with the kit to collect a soil sample and test it.

Adjusting Soil pH

If your soil’s pH is outside the ideal range for Phacelia Tanacetifolia, you’ll need to make adjustments to bring it into the optimal range.

Lowering Soil pH (Acidic Soil)

If your soil is too acidic, with a pH below 6.1, you’ll need to add lime to raise the pH. The amount of lime required will depend on your soil’s current pH, buffer pH, and the desired pH level. Consult the instructions provided with your soil test kit or seek guidance from a local gardening expert to determine the appropriate amount of lime to apply.

Here’s a general guide for adding lime to lower soil acidity:

Current Soil pH Lime Needed (per 100 sq ft)
5.5 – 6.0 10 – 20 lbs
5.0 – 5.5 20 – 30 lbs
Below 5.0 30 – 40 lbs
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Apply the lime in the fall or early spring, allowing it to react with the soil before planting your Phacelia Tanacetifolia.

Raising Soil pH (Alkaline Soil)

If your soil is too alkaline, with a pH above 7.8, you’ll need to add elemental sulfur or a sulfur-containing fertilizer to lower the pH. Again, the amount of sulfur required will depend on your soil’s current pH and the desired pH level. Consult your soil test results or a local gardening expert for the appropriate amount to apply.

Here’s a general guide for adding sulfur to raise soil acidity:

Current Soil pH Sulfur Needed (per 100 sq ft)
7.5 – 8.0 2 – 4 lbs
8.0 – 8.5 4 – 6 lbs
Above 8.5 6 – 8 lbs

Apply the sulfur in the fall or early spring, and allow several months for the pH adjustment to take effect.

Planting and Caring for Phacelia Tanacetifolia

phacelia tanacetifolia 2Image source: Pixabay

Once you’ve adjusted the soil pH to the ideal range, you can proceed with planting your Phacelia Tanacetifolia seeds.


  • Press the seeds into the soil, covering them with approximately 1/8 inch of soil.
  • Keep the seeds consistently moist during the germination process.
  • Sow the seeds in early spring, as Phacelia Tanacetifolia can tolerate light frost.
  • Thin the seedlings to 12 inches apart once they have sprouted.

Ongoing Care

  • Phacelia Tanacetifolia prefers well-drained soil and can tolerate hot, harsh conditions, but it also adapts well to other environments.
  • Provide the plant with a minimum of 6 hours of direct sunlight per day, though it can also tolerate partial shade.
  • Maintain consistently moist soil during germination and initial growth, but the plant can withstand moderate drought once established.
  • Use compost-rich soil blends to provide optimal growing conditions.
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By following the steps outlined in this guide, you can successfully balance the pH of your soil to create the ideal growing conditions for your Phacelia Tanacetifolia plants. Remember to regularly monitor the pH and make adjustments as needed to ensure your wildflowers thrive and bring their unique beauty to your garden.


  1. Outside Pride – Lacy Phacelia Wildflower Seed
  2. USDA – Phacelia Tanacetifolia
  3. Epic Gardening – Phacelia