Oriental Lilies - Allelopathy - Caffeine

Kenneth Hixson khixson@nu-world.com
Thu, 23 Oct 2008 10:37:00 PDT
C.J. Teevan wrote:
 >used coffee grounds

	In my experience, coffee grounds do add organic matter, minor amounts 
of chemicals, and seems to be attractive to earthworms, at least if 
mixed with other composted organic matter.  I haven't seen anything 
about long term effects on lilies, oriental or otherwise.  In my garden, 
slugs/snails are a problem while the lilies are emerging and until the 
new growth is about a foot high, but when it toughens up, the slugs are
no longer attracted.  Unfortunately, the only effective treatment I've
found is the old fashioned metaldahyde baits such as Deadline.  Iron
phosphate has been only marginally effective.  Others, such as wood 
stove ashes, egg shells, etc, are not effective in our rainy spring
weather.  I'd love to hear of an organic treatment that works.

	The following is on the website of Paghat the Ratgirl, (who is a man), 
and a person of definite opinions--which you may or may not find acceptable:

> http://www.paghat.com/coffeeslugs.html
> The Hilo study has commonly been misrepresented as proving coffeegrounds
> kill slugs, when it did nothing of the sort.  The Hilo station was first
> to establish that a SPRAY of 1-2% chemical caffeine (NOT coffee, certainly
> not coffeegrounds merely cast on the soil) dousing the ENTIRE plant will
> over time lower the slug population by killing just the BABY slugs &
> snails AFTER THE TREATED PLANT IS EATEN. It has zero protective value
> except in the long run of controlling the number of slugs that live to
> maturity. The use of coffeegrounds per se was shown in other studies to
> have little to zero effect, there being only a couple brands of coffee the
> FRESH grounds of which would even reach the toxic level required, & spent
> grounds already leeched of caffeine would be especially harmless. Even the
> effective spray of caffeine in solution required the treated plant to be
> eaten to kill the youngest slugs only.
>> and there are no known problems with other
>> species.
> If one overlooks the harm done to species of plants. Caffeine if used
> effectively as a REGULAR application of 1-2% chemical solution sprayed all
> over the plants, according to Usherwood's follow-up to the Hilo study, the
> plant itself responds to the caffeine, is toxified & damaged. It's true
> casting grounds on the soil is pretty much a harmless activity & even
> functions as a slow-release acid fertilizer, so no harm done, but also no
> harm done to slugs.



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