I don't know the quantities are significant enough to cause problems but I am not experienced in the use of Sulpomag. In the absence of direct knowledge; is it possible to set up some sort of temporary barrier? Not much will stop a cat that wants to get into something but normally you can unmotiviate them from going to that specific spot.

What info I could find online suggests it should be Alright to use this product, if used properly. However, I've never used this product myself. :) So I cannot speak from personal knowledge. Just from researching it.

~Tina

You could also use a sprinkler head with a motion sensor. It turns on when there is movement in front of te sensor and turns off within 1 or 2 seconds.

They are sensitive enough to pick up a cat at distances less than 15 feet.

Thanks for your wonderful suggestions and advice!

So far I'm leaning towards the temporary barrier idea; it'll keep those curious paws and noses from the treated area. Maybe plastic tarp weighted down with a few heavy rocks should do the trick? The plumeria canopy keeps the root zone pretty shaded so hopefully I won't inadvertently solarize the soil underneath.

Thanks again everyone!