I thought the ammonia solution was only for killing the slugs directly. I didn't think it had a residual effect.

I hope someone else can clarify.

Yes, it only kills on contact.
I spray between 1-2am when they're out there
munching away on my hosta.
I'm just wondering how much spraying is too much.
Can it burn the leaves or hurt the plant in any way?
SASSY

I've used only vinegar solution but I noticed it browned the foliage on some of my other plants but never harmed my hosta... I would worry the same about the ammonia

Vinegar is often used as an herbicide, so that explains browning on some plants.

thanks melissa =)

Does anyone know the answer to my question?
Sassy

This thread provides observations about ammonia's effect on plants. Also, put "ammonia" in the search box at the bottom of the forum front page, and find several other threads on the subject.

Here is a link that might be useful: Ammonia & snails thread

Sassy, I would guess too much of anything can be harmful. If you are out to kill ever last slug - good luck. I look at slug control as what is the least I can do to achieve the result that I want. For every garden it might be different - so far my north and east garden need very little spray, but my south and west gardens require more attention.

Paul