I moved several months ago. Before I moved, my cats used the great outdoors
for their 'business', only rarely using the litterbox I had indoors. When I
moved I had to keep them indoors for awhile to be sure they wouldn't run
away, and they got used to using the litterbox.

Then I got a cat door put into my sliding-glass window so they can freely
come and go as they wish, which they learned to do. However, they did not
resume doing their business outdoors - they continued to use the litterbox,
while I wanted them to resume their previous behaviour and use the outdoors
for the most part, of course. So I removed the litterbox and after only one
minor incident, I was happy to see that my cats resumed doing their business
outdoors. But unfortunately, they are doing their thing in the gravel patio
that is immediately outside my window. There's plenty of garden and dirt and
bushes around the patio, and for that matter, they have the run of the
neighborhood, but they do it ALL on the patio.

I'm renting a room at my new residence, and this isn't going over well at
all with the owner, and I'd love to know of a way I could induce my cats NOT
to use the gravel patio and either go in the garden or surrounding bushes or
elsewhere in the neighborhood.

I put the litterbox back in my room, where it was, thinking I'd just have to
get them back on it, but they are used to the patio now and are not using it
much at all. Perhaps if I kept them indoors for a few days so they'd get
used to the litterbox again, they would continue to use the litterbox when I
let them go in and out again, but what I'd really like to do is just get
them off the patio and into the garden/bushes for their 'business.'

Any advice greatly appreciated,
-dg