In message , ken cohen
writes
I am going to be using glyphosate on my new allotment shortly but I'm
very concerned that the stuff might easily get blown onto my
neighbour's plot, which is very well cultivated with various
flourishing plants. The instructions say wait for a windless day, but
you can never be sure about that.

You shouldn't be using it if there is sufficient wind to cause spray
drift. Some plants and many seedlings are exquisitely sensitive to
herbicides. You don't want to use any aerosol spray if there is wind -
fine particles can drift a long way. And you always get fine mist when
spray hits the leaves.

Just thinking out loud about this,
might it not be an idea to spray it onto black plastic sheeting first,
and then lay the plastic on the ground, secured with bricks or
whatever?

If you must use a weedkiller on a windy day then do not spray it at all.
Spray hitting any surface will always generate some even finer spray.

If you can't wait then use a paint brush to apply it as a precision spot
weeder. ISTR someone sells a glyphosate based spot weeder using shoe
polish packaging and wet sponge technology. The implementation is
rubbish but there is no reason why it cannot be made to work.

Regards,
--
Martin Brown