Welcome to GF. I don't have cave geckos, but I have a lot of planted tanks for my day geckos, Rhacs and fat tail geckos. Plants should be no problem as long as you find types that will grow well under the tank conditions. I've had best luck with pothos which will grow anywhere. Some people put a potted plant into the cage. I prefer to actually plant the tank. This involves a layer of hydroton expanded clay balls, vinyl mesh and coco fiber. Google to find out more.