How long does 'Round-Up' take to work

portboy

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Put Round Up on a whole lot of weeds in the back garden yesterday...anyone know how long it takes to work...doesn't actually say on the box ?
 
Could take 10-14 days. The principle is that the roots are killed off first and then the leaves die because the roots are dead.

Don't worry, it will happen but you must have patience!!
 
Having said that, I used Roundup many many years ago and it worked fantastic. The last time I purchased it I found that it didn't work as well. I thought that the manufacturers might have watered it down a bit?
 
I used it in the depths of winter when there was zero growth (its only recommended for use during active growth) and eventually it worked 100%. It just took a long time.
 
I have used Round-Up twice during growing season and found it worse than useless.
 
It is pointless using Round Up when it is raining. It needs 3 or 4 four days to sette and get working. After that it will work, but be very careful - the fumes from it are Toxic.
 
There seems to be a bit of misinformation here. Roundup will work in the winter, it just takes longer. On a summers day it will start to kill weeds within 2-3 hours, with visible signs in within 4-5 days it takes 6 or more hours in the winter. If it rains it will be much less effective. Roundup fumes are not toxic, it's a herbicide not a pesticide so try not to drench yourself in it or drink it. If you use a mix of 1 litre of roundup for every 40 litres of water it will be devastating.
 
depending on whether it roundup pro biactive or the pre mixed squirter bottles, and weather i.e rain about 3-5 days
 
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