WeedBlock Premium 3 Year Landscape Fabric For Weed Control, 3 feet x 100 feet WeedBlock represents the latest development in weed control fabric technology; Made of UV-treated polyethylene Patented Microfunnels allow water and air to penetrate to the soil, helping conserve moisture but preventing weed growth Microfunnel design allows air to constantly circulate to and from the soil, keeping it from souring or mildewing All plants need light to grow, including weeds. WeedBlocks patented Microfunnel design tapers at the bottom to block 92% of the visible light WeedBlock Landscape Fabric not only deters weeds, it encourages root growth by keeping soil moist and cool; Chemical free, easy to use weed barrier