hang,

Interesting idea. You could advertise on local Craigslist or set a website people can Google. I tried Googling "Plant Sitter" or " Plant au Pair" in my area and all I get is How-To sites. So it seems to be an open field. The only difficulty is getting the your info out there without confusing it with the many other plant care info sites. One could tie your site to a local nursery where they recommend your services and if you are searching for someone that may be the place to start. aloha