What is the fastest and safest way to lower the ph of a lawn? I have 7 lawns that the ph is 7.0 to 7.4. All are centipede. I have never applied sulfur to a lawn before. I have read that aluminum sulfate is the quickest but it will burn the lawn. I know SCU and ammonium sulfate will lower the ph but doesn't this take a while? Thanks for any advice in advance.