Roofers Torch and a 15Kg tank of propane. You can even get a tripple burner one now for gardening.

Don't use salt, it will wash wherever the rain and then groundwater takes it.

Sodium Chlorate is an old and persistent weedkiller if it is still available.

As for the pond, what do you think plastic sheeting was invented for , it only needs to be covered while you spray.

__________________
Always thank people who have helped you immediately, as they may not be around to thank later.
Visit my blog at http://podsplot.blogspot.com/
I support http://www.hearingdogs.org.uk/