HiI have 6 coco lined baskets on my front porch that I plant petunias in every spring. Problem I have is over the winter – moss will grow in the soil of these baskets and gets so hard packed I end up having to take out all the soil & start over every spring. Is there a way to prevent this moss? If I put plastic on the top of the baskets & add mulch to hold it down from the weather (gets windy here in Wash.) would that work to stop moss from growing? Or would that just make mold grow? Gets expensive having to fill these baskets every spring because of this moss problem.