Originally Posted by Smallaxe
The claim is that the 'acid', washes out in the coffee making process, so all the acid is now in your cup, not the grounds... like pine needles,,, not a contributor to acid soils...
If worms love them then that alone will create fertile soil, if it builds a population...
If be curious to know the truth about this. I've always heard to throw coffee grounds on hydrangeas to keep them blue (because of acidity), is this an old wives tale then? Also, can you explain why pine needles don't add acidity to the soil?