Plastic film construction

A roll of greenhouse film comprised of a large tubular plastic sheet having flattened longitudinal edges at least two plies in thickness, such edges being folded over about 180.degree. toward an imaginary line drawn longitudinally along the upper median portion of the sheet such that there are at least four plies on each side of the imaginary line, said tubular plastic sheet further having a median surface longitudinally slit the length thereof thereby providing a pair of free film edges, said slit constituting or being proximate to the imaginary line, the so-folded and so-slit tubular plastic sheet being longitudinally rolled over the imaginary line into a cylindrically shaped object or roll in which said free film edges are separated from the superposed roll by at least two plies of said folded plastic sheet.