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Posted to uk.d-i-y
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Glyphosate kill delay
On 13/08/2013 10:25, wrote:
On Monday, 12 August 2013 11:52:46 UTC+2, Windmill wrote:
Does anyone know how long glyphosate takes to kill various weeds?
E.g. elderberry bushes, dockins, brambles, bracken, grass?
Don't want to waste money by spraying again if it's premature to do so.
Seems to vary enormously. About 10 years ago, I would use Roundup against broad leaf weeds on a hot day and see them visibly start to wilt within 2hrs at most and they'd be flat out dead in a couple of days. Try using today's Roundup formulation, however, and you'll be lucky to achieve any knockdown at all.
Monsanto a couple of years back were selling something they called
"fast" Roundup that was more than just glyphosate. It made home users
aware that something was going on within a couple of days.
The way that glyphosate works by inhibiting certain chemical pathways
means that it takes a week or more before the photosynthetic byproducts
build up to levels that are toxic to the plant. The growing point is
usually affected first - nettles turn a nice shade of yellow as it takes
effect and grass a characteristic bronze as it expires.
I have give up with Roundup and Weedol. I buy some cheap stuff from Wilko in sachets that is supposed to be watered down, but I apply it neat. Still takes about 2 weeks to kill the weeds off, though.
Sounds like a major failure to RTFM is causing to your problems.
Any generic glyphosate product will do the job apart from on a handful
of Roundup Ready(TM) volunteer weeds, waxy holly and ivy and curiously
buttercup which is surprisingly resistant to the stuff.
--
Regards,
Martin Brown
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