Not to quote my favorite movie or anything, but regarding Agent Halt and what you described using it for:
“I do not think that means, what you think it means”
Check the product description again…but I sincerely can’t comment on their mixing ratios any more than they have provided.
I’ve emailed power wash store and asked them directly if it’s safe to use in plants and the answer was yes. Here’s another Facebook post that I found interesting.
I’ve never had issues when using halt. I’m huge on rinsing so that could be the main reason too but always spray some halt on questionable plants after a roof cleaning. I like it on spraying equipment down too. I find milorganite around downspouts and run off areas pretty helpful and that stuff is really cheap.