You could just build a cover for so easy and cheap. All that you really need is a painters tarp and some pvc, put it together and you have a cover. A cover though would really help with the moisture and humidity.
Also I'm not sure how much they are but you could pick up a dehumidifier. The only thing is you would probably have to empty it every day.
Also I'm not sure how much they are but you could pick up a dehumidifier. The only thing is you would probably have to empty it every day.