The number-one fabric selected by consumers, WeedBlock stops weeds without chemicals. Designed with patented Microfunnels, the fabric blocks light but allows water and air to penetrate to the soil, thus helping conserve moisture but preventing weed growth. The special 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. WeedBlock's patented Microfunnel design tapers at the bottom to block 92 percent of the visible light, stopping weeds from growing. The special construction is formulated to help the fabric last for years under direct sun exposure or indefinitely, if protected from UV rays by bark mulch or stones.