Artificial Grass Underlay 4m x 5m. About the Artificial Grass Underlay 4m x 5m Manufacturer: AquaGrass Artificial Grass Underlay. Premium geotextile to ensure that no weeds or grass push up through your artificial turf. Specifications and pricing on this page reflect the data published by the source retailer at the most recent catalog refresh. Verify the current listing on the retailer page before purchase.