"BCL" wrote in message
...
I was busily spraying the gardener's best friend (Roundup) along the
fence and various other places when it occurred to me to wonder if it
is more effective sprayed in the morning or evening or even mid day.

I have had (rare) occasions when the spray has had little effect on
the weeds/grass and wonder if the plants absorb it better at some time
rather than others. This doesn't include it being washed off by rain.


Any thoughts?

We always spray in the morning at work.
1) Because for greens it's before the golfers get out.
2) In summer it's a common job
Weed spraying in gardens starts in the morning and runs all day when weeds
are growing well.
We have not noticed any difference in times. A heavy dew means we may waste
a little more chemical on weeds as you feel the need to "wash" off the dew
with the chemical.
As long as the weeds are actively growing, aren't wilting from drought,
aren't covered in dust (for roundup esp) or aren't waterlogged, there
shouldn't be too much difference.
But yeah, we have sprayed in quite hot weather, sometimes mid 30's and the
roundup works well.
I too have noticed roundup seems to have different effect. In fact once I
noticed how much better it worked at home than at work. A couple of guys had
to go get their spray ticket and were told using dam water for mixing isn't
good. We changed at work to tap water, and it did seem to work better.
Maybe the water you used was dirty?
Other than that, no idea, out of date chemical?


Regards
Bruce