Fabric Grow Bags are made of double-layer felt fabric instead of plastic. This felt-like fabric allows for great aeration so your plants will not suffer from heat build-up, overwatering, or poor aeration. Plant Bags have a porous fabric that air-prunes plant roots, resulting in a robust and healthy root system. With the combination of air root pruning creating a better root structure and the aeration of the root zone, your plants can reach their full potential.