Controlling the direction of the growth is important in the new vines to give easy access for air flow management, sun management, and provide adequate support for stress-free vines. When young vines are being trained, the green tape helps to hold the two producing vines, or 'cordon', to the wire. Our smallest vines still have milk cartons around the base, which we use in lieu of snow banks to help keep the young vines insulated during the winter. We purchase end-run or over-stock milk cartons from various dairies, and the waxy paper stands up to the water and helps keep the vines protected from wind, snow, and nosy small animals. After two or three years the vines are strong enough, and the tattered milk cartons are collected, their work is done.