Oriental Lilies - Allelopathy - Caffeine

Jane McGary janemcgary@earthlink.net
Thu, 23 Oct 2008 17:17:45 PDT
This is purely anecdotal, but there is a place on my driveway that I 
regularly toss the dregs from my press coffeepot, and I've been 
noticing that it has fewer weeds than the surrounding gravel. Maybe 
coffee grounds are not so good for plants in concentrated doses, 
though it's often recommended to add them to compost.

Jane McGary

At 12:57 AM 10/23/2008, you wrote:

>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?

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