For months, I have been collecting by the garbage bagful, courtesy of my local Starbucks, large plastic sacks of their used coffee grounds for my garden.
It is my understanding that those used grounds block slugs from slithering up the stems of my dahlias and lilies. In the Summer of '08, I used smaller amounts sprinkled around tomatoes and strawberries, but they seemed to taste a bit like coffee afterwards, so I don't do that this year.
With my much greater quantities of grounds, which are only mildly acidic, I figured the grounds would pour Nitrogen and organic matter into the Soil and improve the tilth of my high clay Long Island dirt.
Last week, I stumbled on some research about Allelopathy. Coffee beans are Allelopathic to among other things themselves. I am wondering if they might be Allelopathic to the $100 worth of Oriental Lilies I just purchased and planted in the newly dug heavily amended bed I reserved just for them. Anyone out there who can tell me not to worry about this?
Catherine, Long Island