Moisture/fungus in the trunk

I had my Ford Escort ’95; 3 doors; sliding roof; rear spoiler, almost half a year outside. Because I lacked the money for repair measures and the TüV, I then registered the car and left it on the yard. In the meantime I rented a garage and looked into the car after a long time and then had to find out that my suitcase was actually very wet. Already so wet that I can send the car to the hairdresser (kotz). I still noticed that I was the rubber of the rear window already has wild growth. But since always moisture comes in I exclude this as a watch thing. Can someone help me? The car was dry before when I was driving with it.