[Theunz]

There is no doubt that grass growing under a vechile can help transfer moisture to it. I would think that the closer the grass is to the bottom of the vechicle the more moisture would be transferred. If I was to store over grass I would cut it as short as possible, maybe even spray something like RoundUp on it. As far as having the jacks down; mine is stored inside, and not only are the jacks down, they are lifting the tires slightly off the ground. I left mine like that for a full year, while I was dealing with cancer, with no detrimental effects.