My buddy just did his TDB using Diamond Mesh Safety Fencing.... It's the stuff you see at construction sites. He covered his boat in it, then attached the grass to that. If you are using rafia or grass matts you can detach the fence at the end of the season, store it and use it again next year.
http://www.jitlab.com/Diamond-Mesh-Safety-Fence-p/lss-145622mp.htm?1=1&CartID=0