These synthetic white fabrics protect plants from cold, insects and wind. Allows light, air and water in. Can be placed over 9 gauge wire hoops or lain directly on plants. Extends season for winter greens, early tomatoes, etc. A physical barrier row cover impedes flea beetles, cucumber beetles, squash vine borers, etc. and hence provides pest control. Care must be taken on young seedlings in summer: remove during very hot days.