How long does 'Round-Up' take to work

[portboy]

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 ?

[kbie]

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!!

[BOXtheFOX]

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?

[serotoninsid]

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.

[croman]

I have used Round-Up twice during growing season and found it worse than useless.

[mercman]

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.

[olafshiel]

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.

[sblandscapin]

depending on whether it roundup pro biactive or the pre mixed squirter bottles, and weather i.e rain about 3-5 days