How to Acidify Soil for Blueberries

Blueberry plants are pH sensitive, thriving in acidic soils.

Blueberry plants grow best in rich, deep, loose, well-draining acidic soil. In more alkaline soils, blueberry plants do not adequately absorb nutrients through their roots. Signs of improper pH levels include small yellow leaves with contrasting green veins and stunted new growth.



In very alkaline soils, amend soil in the fall for spring planting. Soils made alkaline by materials high in calcium, such as limestone or recent construction, cannot easily be acidified and soil amendments will only work temporarily to lower the pH; in these circumstances, consider growing blueberries in raised beds.

Things You'll Need

• pH testing kit
• Sulfur
• Hoe
• Shovel
• Peat moss, one 4-foot cubic compressed bale per 5 blueberry plants
• Compost
• Pine bark or sawdust

Instructions

1. Test pH according to directions in your soil testing kit for water pH value. Blueberry plants thrive in acidic soils with a pH of 4.0 to 5.5.

2. Add sulfur if the pH is above 7.0 in the following quantities per 100 square feet of soil: If soil is light and sandy, add 3/4 lbs.; if soil is a medium, sandy loam texture, add 1 1/2 lbs.; if soil is a heavy, clay loam add 2 1/4 lbs. Till sulfur applications into the soil immediately. Recheck soil pH levels 60 to 90 days later before planting.

3. Hoe planting area to loosen soil 1 foot deep if pH levels are 5.5 to 7.0. Remove at least 1/3 of the soil. Replace the soil with an equal amount of pre-moistened peat moss. Combine the peat moss and remaining soil. Recheck soil pH levels 60 to 90 days later before planting.

4. Top dress blueberry plants with compost at planting time to buffer soil pH. Then mulch with 2 to 4 inches of sawdust, peat moss or pine bark as a slow-release soil acidifier.

Tips & Warnings

• Soil pH tests are available through university extension offices.

• Application of fertilizers such as aluminum sulfate for several years can acidify soils.

• Follow directions and observe precautions on sulfur label.

References

• Oregon State University Extension: Acidifying Soil for Blueberry and Ornamental Plants in the Yard and Garden
• University of Minnesota Extension: Blueberries for Home Landscapes
• University of Florida Extension: Blueberry Gardener's Guide
• eXtension.com: What Products Can I Use to Lower the Soil pH Around my Blueberries

Resources

• University of Florida IFAS Extension: Soil pH in the Home Landscape or Garden