Holidays and Traditions What is a blanket filter? What is a blanket filter? Filter blanket means a layer or combination of layers of pervious materials (organic, mineral, or synthetic) designed and installed in such a manner as to provide drainage, yet prevent the movement of soil particles due to flowing water. Related Posts:Plants need things to grow in order for them to survive.Mealworm frass is a potential biofertilizer.How to bring dead olives back to life in a pot? 149 Dead Olive Tree Photos - Free and Royalty-Free Stock Photos from...How to replace the fuel filter on a lawn mower.