According to FIFA: > FIFA mandates **natural grass for all World Cup matches**. > To prepare, all host stadiums with artificial turf (such as MetLife Stadium, Gillette Stadium, Mercedes-Benz Stadium, and SoFi Stadium) had their synthetic turf replaced with temporary **natural grass or hybrid grass pitches.** > **Hybrid pitches are made of living natural grass with synthetic fibers stitched or mixed in** for extra durability. The temporary fields are grown off-site, transported in, and laid over specially designed sand and drainage systems