Black + White Poly Film, 10 ft x 100 ft, 4 mil, Folded Roll

A 4 Mil Poly Film for Sealing a Room Fast

Grow rooms leak light in two directions, and both cost you. This film is polyethylene with a black face and a white face. The black side blocks light passing through, which matters for light deprivation and for keeping a dark period dark. The white side reflects, and Hydrofarm rates it above 90% reflective. A single roll covers 10 ft wide by 100 ft long. It arrives folded to roughly 3 ft, so one person can carry and unfold it. Staple it, tape it, or hang it from a batten across the ceiling. The material is waterproof, so wall damp and condensation stay off the drywall behind it. It is also tear resistant, though this is the thinner of the two gauges offered. Rooms that get bumped by carts and ladders usually step up to the heavier sheet.

Where Light Blocking Greenhouse Film Earns Its Keep

Two jobs come up over and over. The first is lining a room so light bounces back at the canopy instead of dying on a grey wall. The second is blackout, whether that means a light-dep greenhouse or a flower room next to a window. One roll usually handles both if you plan the cuts before you start. Measure the walls, add a hand's width at each seam, and cut on the floor rather than up a ladder. Overlap seams and tape them, because a pinhole is a light leak. Keep the white side facing in on walls and the black side facing in on blackout panels. Run it behind the lights, not across them, so heat has somewhere to go. Replace panels that go brittle at the staple line rather than patching them.

Key Features

• Thickness: 4 mil polyethylene, the lighter of the two gauges offered
• Size: 10 ft wide by 100 ft long on a folded roll
• White Side: rated above 90% reflective for walls and floors
• Black Side: blocks light for blackout and light deprivation work
• Waterproof: keeps condensation and wall damp off the surface behind it
• Folded to Carry: arrives about 3 ft wide so one person can move it
• Cut to Fit: trims with scissors or a blade and takes staples or tape

Technical Specifications