Sod grower Pat Hogan installs a new variety of turf that needs less water and fertilizer. Kevin learns how interior designer Robin Gannon came up with the design for the great room entertainment center, then meets Matt Allen to see how he's turning her design into reality, with the sliding barn door hardware he's using to hang the salvaged interior doors that will conceal the TV. In the basement, Richard shows Kevin the finished mechanical room. On ASK THIS OLD HOUSE, Roger helps a homeowner replace a mailbox that was damaged by a snowplow. Kevin shares some information about window anatomy. Tom helps a homeowner reuse an old door in a new opening. And the guys ask, "What is it?"