Line the basket with plastic cut from a sturdy plastic bag. Fill the lined basket with vermiculite potting material. Water it lightly so that it's moist but not soaked. Remember that the basket has no drainage, so don't over-water. Sprinkle the soaked wheat grass seeds evenly over the surface of the vermiculite.
Press seeds in lightly.
With scissors, trim away any plastic that extends above the edge of the basket. Cover the entire basket with an inverted brown paper bag, or drape it with newspaper or cloth. Place the basket in a cool spot away from direct sunlight until the grass sprouts. Check every day. Do not let it dry out.