My new pond is low down and has some water runoff. Unfortunately the stoned areas in the hill behind has some major weed issues, I am wondering if there is a weed killer I can use that is harmless to fish?
I know it is ideal to not use weed killer around the pond but I pulled all the weeds a couple of weeks ago and they are already a foot tall again
As weird as this may sound, I use aerosolized non-chlorinated brake cleaner for weeds if I have to go the chemical route (though I try not to, but sometimes I need to). I use it because it is very effective at killing weeds, even though it isn't advertised as such, and it is a very volatile liquid that evaporates almost immediately, rather than sinking into the ground. There are no long-term hazards to chronic exposure, like there are with most herbicides. If it could get in the pond directly while spraying it, I definitely couldn't recommend it, but if you're just worried about weed killer soaking into the ground and then making its way into the pond, than this may be a good solution since it will evaporate rather than seep into the ground.
