Maintaining blueberry potting-soil pH



Thank you very much for answering my previous question. One more question I have is, how do I keep the potting-soil/growing medium for blueberries low in pH (acidic) over the months and years? As I understand the soil loses it’s acidity due to various reasons, one of them being the water has alkaline in it.

Thank you.


Thank you for contacting the Toronto Master Gardeners with a follow-up question about your blueberries. Maintaining an acidity level of pH 4.5-5 in the growing medium for your blueberries is important so that the plants can absorb nutrients. Here are some ways to maintain the acidic pH level:

  • Use ericaceous soil (specially formulated for acid-loving plants) if you can, or a 50-50 mix of potting soil and peat moss. A growing medium that doesn’t contain peat is more environmentally-friendly.
  • Use rainwater for watering as much as possible, since tap water is usually alkaline.
  • Add mulch to the top of the soil so that you won’t need to water as often.
  • If you are going to fertilize use a fertilizer for acid-loving plants.
  • Remove and replace about 1/3 of the soil from the top of the containers every spring.
  • Totally replace the container soil every 2-3 years.
  • Test your soil every spring to check the pH level (soil testing kits are widely available at nurseries and home centres).
  • Monitor your plants for yellowing leaves. This could be due to chlorosis which is an indicator of a change in acidity level.
  • Be patient and let your plants develop. You probably won’t see any blueberries until the third year after planting.

Best of luck with your blueberries !