Acidic Soil Amendment


What renewable resource would you recommend to make soil more acidic? For example, I am growing blueberries in pots and have added inkberry to my garden, both of which like acidic environments. Thank you in advance.


One of our Ask a Master Gardener posts, Blueberries , discusses how to create a more acidic soil environment  (e.g., mixes for acid-loving plants, use of pine needle mulch).  The link in our post for the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) has expired – see the Ministry’s current Fact Sheet – Blueberries for home garden – in particular, the section on sources of organic matter (well-rotted manure, straw, compost, aged sawdust) will be of interest to you.   Wisconsin Horticulture’s Growing blueberries in containers suggests use of sphagnum peat moss/pine bark, coir/sphagnum peat moss and perlite as good acid growing media for blueberries.

I suspect that you are concerned about using peat moss, which is a non-renewable resource that is often recommended to acidify soil. For additional information, see an earlier post on the Ask a Master Gardener site,  Peat moss – pH, which suggests alternatives like coconut coir. (note the difference between sphagnum peat moss and peat moss)

If your garden soil is not acidic enough to keep your inkberry happy,  add well-decomposed compost, pine needles, bark mulch and leaf mold and/or elemental sulfur, to lower the soil pH.  Oregon State University’s Acidifying soil for Blueberries and Ornamental Plants in the Yard and Garden provides additional details on how to acidify soil.

Some experts suggest testing your soil pH every spring – you can buy pH testing kits at nurseries and big box stores.  Do some research before buying testing kits/pH meters, as there is considerable variability in accuracy and ease of use among these products.

May 30 2021