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Bold Tarps for light deprivation by Americover.
Bold Tarps for light deprivation by Americover.

What should you consider when buying a light deprivation tarp or cover for your greenhouse and what are your options? There are four primary types of black-out light dep covers currently on the market.

  1. Panda is a Black/White polyethylene film that is typically 4-6 mils thick.
  2. Woven Coated Poly Black/White is a non-stretch woven material coated with white poly on one side and black on the other side, usually 9-12 mils thick.
  3. Breathable light deprivation covers are made from layers of Black and White fabric not polyethylene sheeting, available in 6-30 mils thick.=
  4. BOLD is a string reinforced polyethylene film with a solid white and solid black side, without pinholes and 8 mils thick.

Sponsored article from Americover! Bronze sponsor of the 2nd annual Ganjier Spring Kickoff on Feb. 20, 2016.

The main goal of a light deprivation system is to ensure total darkness so farmers can force plants to flower during a time they normally wouldn’t, so using the right cover is essential to the success of a crop. Consider whether you will be using an automatic system or manual system in your greenhouse. If you’re manually operating light cycles, you definitely don’t want anything too heavy or anything that rips as you are pulling it over your greenhouse. Poly sheeting gets heavier as it gets thicker, but too thin and it will tear easily.

Panda may be the cheapest and lightest but …

Of the four types, Panda is the least reliable in an outdoor greenhouse. The material is too thin to completely block light, and one rip means you need to replace it.  This can really add up if it has to be replaced every season or even several times throughout the season. Panda film is a well known product, but it lacks consistency. Depending on where you buy it, sometimes it’s a bright white and black while in another store it’s gray and black. This film has been around a long time and is often manufactured out of the county — as a result, it can contain a number of hazardous chemicals that could off-gas.

Woven Coated Black/White can be a good alternative to the Panda film

This tarp is heavier and the woven ribbons of high-density polyethylene give it superior tear resistance, but most woven coated poly covers contain pinholes that allow light to enter.  Although this cover contains UV inhibitors that prevent premature aging, once the polyethylene coating wears off, it will no longer be effective as a light deprivation cover.

Breathable light dep covers go inside the greenhouse under a waterproof cover

This is not designed to be used on the outside.  A breathable fabric is great for air flow and it can reduce excessive heat and humidity build-up.  However, if the fabric gets wet, it creates the ideal environment for mold to grow.  It is also the most expensive cover in comparison to any of the films mentioned in this article.

The BOLD Black Out Light Dep covers contain a layer of diamond shaped polyester scrim reinforcement.

This string is sandwiched between two layers of virgin polyethylene sheeting.  The film is lightweight and flexible like Panda, but has the added durability of scrim to maximize tear resistance.  It isn’t coated like the woven material so it won’t rub off under daily covering and uncovering, and can last through a few growing seasons.  It is not a breathable fabric, so proper ventilation is required but it is waterproof.  There are products on the market very are similar to BOLD but differ in mil thickness, weight and some even contain perforations that allow light to shine through. BOLD is the only 8 mil, lightweight light deprivation cover without pinholes that blocks 100% of light, is made in the USA and is FDA and USDA compliant.

With so many options on the market, it’s difficult to make a decision on which one will work best with your set-up.  Americover has been the ultimate source for specialty plastic sheeting for over 23 years so we know a lot about the different plastics and covers available. We offer a wide range of products that fit the needs of many different applications. If you have questions regarding any of the materials mentioned please call us at 800-747-6095 and speak with a representative or email us at inquiries@americover.com.

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