I just built a new raised garden bed in west central florida, using home made compost and store bought dirt with food in it as well as some cow manure and sea grass from the gulf of mexico. I covered the bed with black weed control fabric over the past week and it has rained every day, all day some days. I went out today thinking I'd start planting and there is a white stuff on the weed fabric which I pulled off and a lot of white stuff on the soil. Actually I used a peice of weed fabric that was more plastic and a piece that's more fabric and the white stuff is by far more on the fabric one and far less on the plastic one. There are no plants in this garden. I assume it is a fungus but beyond that I know nothing nor what to do now. Any help is appreciated.