I have a 10 x 12 porch on the house we just bought. It is enclosed, but no completely. We added lattice to the iron framework from ground to rail, looks nice, but now the cats can crawl underneath and I cannot. They sure enjoy pooping under there and we really do enjoy sitting on the porch, but only if there is a stiff breeze.
I tried processing orange peels and spreading them underneath by sweeping them through the gaps in the deck wood. It seemed to work for a week and smelled great as well. But they wore off I suppose, I don't know if by processing them they lost the citrus that supposedly repels the cats. We've also had alot of rain recently... I'm going to try again with bigger pieces.
As for the pepper I've read about (black, chili, red pepper flakes), tried em all, wasted alot of spices. I've read coffee grounds would work, but this seems expensive and I think those would have to be replaced frequently as well. I cannot put a motion sprinkler there, we'd get soaked as well.
Next project, I've pruned several rose bushes to some extent, I'm going to try lining the entry spots with the briars...
I haven't really answered the question, but I hope I've kept you from taking the time and spending the money to try some of the other suggestions I've heard of. I could use a bit of advice here if anyone has a brilliant idea. I would really like to border the porch with a flower garden, so any plants that repel?
Thanks in advance.