7 Best Greenhouse Film Liners For Freezing Temperatures That Growers Trust

That first hard frost always feels like a deadline, the moment nature tells you the easy growing season is over. But for those of us with a greenhouse, it’s just a signal to shift gears. The single most important decision you’ll make for that shift is choosing the right greenhouse film, and it’s about far more than just picking the thickest plastic you can find.

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Sun Master IR/AC Film: Superior Heat Retention

When the sun goes down on a clear winter day, your greenhouse starts bleeding heat back into the sky. An infrared (IR) film is designed to stop that. It contains an additive that traps the long-wave radiation—the heat radiating off your soil, benches, and plants—keeping it inside where you need it most.

This isn’t just a minor improvement; it can mean the difference between your heater kicking on every 15 minutes versus every hour. The result is a more stable nighttime temperature and a lower heating bill. The "AC" stands for anti-condensate, a surfactant that prevents water droplets from forming on the film’s interior. Instead, condensation sheets off, which means more light gets through and you don’t have cold water dripping on your tender plants, inviting disease.

The tradeoff? On a bright, sunny winter day, an IR film can sometimes work too well, leading to overheating if you aren’t prepared to ventilate. But for most growers in freezing climates, the benefit of retaining precious nighttime heat far outweighs this manageable inconvenience. It’s a top-tier choice for active winter growing.

Ginegar Sun Selector: Diffused Light for Winter

Winter light is weak and low in the sky. Standard clear plastic can create harsh shadows and "hot spots," leaving parts of your plants in the dark. Diffused film, like Ginegar’s Sun Selector series, solves this by scattering the light as it passes through.

Think of it like the difference between a bare lightbulb and a frosted one. The diffused light penetrates deeper into the plant canopy, illuminating lower leaves and reducing the risk of sunscald on the top ones. This even distribution of light is critical for photosynthesis when every photon counts. It creates a calmer, more uniform growing environment.

While some diffused films sacrifice a tiny percentage of total light transmission, the improved quality of the light often leads to healthier, stockier plants. It’s a smart choice for growers who prioritize plant health and even growth over absolute maximum heat retention, particularly for crops like leafy greens that thrive in these conditions.

Bootstrap Farmer Film: Durability for Harsh Snow

There’s nothing worse than waking up to a foot of heavy, wet snow and worrying if your greenhouse is still standing. This is where durability becomes non-negotiable. Bootstrap Farmer has built a reputation on tough, reliable gear, and their greenhouse film is no exception.

Their 6 mil film is made from high-quality resins that provide excellent tear and puncture resistance. This matters when you’re pulling the film tight over the frame during installation, and it matters even more when it’s being hammered by sleet or bearing the weight of a sudden snow load. A cheap film might save you a few dollars upfront, but it only takes one failure during a winter storm to wipe out your entire crop and your structure.

This is about risk management. Investing in a durable, tear-resistant film is like buying insurance for your winter growing season. You’re paying for the peace of mind that your structure’s skin can handle the physical stresses of a real winter, from high winds to heavy precipitation.

Farm Plastic Supply 6 Mil: A Reliable Standard

Sometimes you just need the dependable, no-frills option that gets the job done. Farm Plastic Supply’s 6 mil, 4-year UV-treated film is that workhorse. It’s the baseline against which other films are often measured, offering a solid balance of affordability, durability, and light transmission.

The "6 mil" thickness is the industry standard for a reason. It’s strong enough for most applications without being overly heavy or expensive. The crucial feature is the 4-year UV rating. Ultraviolet radiation from the sun is what breaks down plastic, making it brittle and cloudy. A UV-stabilized film is engineered to withstand this degradation for at least four seasons, ensuring you don’t have to re-skin your greenhouse every other year.

Don’t mistake "standard" for "subpar." This type of film is a fantastic choice for unheated high tunnels, overwintering structures, or for growers in milder winter climates where extreme insulation isn’t the primary concern. It’s a proven, cost-effective solution.

Poly-Tex Tufflite IV™: Four-Year UV Protection

Replacing greenhouse plastic is a major chore. It takes time, effort, and usually a calm day that never seems to arrive when you need it. That’s why the longevity of your film is such a critical factor. Tufflite IV™ is named for its guaranteed four-year lifespan against UV degradation.

This focus on longevity is a smart economic move. A film that costs 25% more but lasts twice as long is the cheaper option in the long run. More importantly, consistent performance is key. A film that yellows and becomes brittle in its second year is also a film that’s transmitting less light to your plants and is more likely to fail when you need it most.

Choosing a film with a reliable multi-year warranty like Tufflite IV™ is about planning for the future. It allows you to focus on growing instead of worrying about maintenance. You install it correctly once and can trust it to perform season after season.

SolaWrap™ Bubble Film: The Ultimate Insulator

If you’re serious about growing through the coldest parts of winter and plan on heating your greenhouse, SolaWrap™ is in a class of its own. It’s not a film; it’s a composite material of heavy-duty polyethylene with encapsulated air bubbles. This design provides a massive insulating boost, similar to double-glazing a window.

The trapped air pockets create a significant thermal break, dramatically cutting down on heat loss. This translates directly into huge savings on heating fuel. The manufacturer claims R-values that far exceed what’s possible with a double-inflated film setup. It’s also incredibly durable, with a lifespan often exceeding 10 years and the ability to withstand extreme snow and wind loads.

Of course, there are significant tradeoffs. SolaWrap™ is a premium product with a much higher upfront cost than traditional film. It also has slightly lower light transmission. But for a grower in a very cold climate (think USDA zones 2-5), the long-term energy savings and incredible durability can make it the most cost-effective choice over the life of the structure.

Grower’s Solution Overwintering Plus Film

Not all winter greenhouse use is about actively growing tomatoes in January. Sometimes, the goal is simply protection—keeping dormant nursery stock, perennials, or hardy greens safe from wind and extreme cold. For this purpose, a specialized overwintering film is the right tool for the job.

These films, often white and opaque, are not designed for maximum light transmission. Their primary job is to create a sheltered microclimate. The white color reflects harsh winter sun to prevent premature budding and temperature swings, while the heavy-duty construction provides a robust barrier against wind, ice, and snow.

This is a strategic choice for season extension. You can use it on a simple hoop house to protect your fig trees or overwinter flats of perennials for an early spring start. It’s a cost-effective way to add a layer of protection without investing in a full-production, all-winter greenhouse setup.

Double Layer Inflation for Maximum Insulation

This isn’t a specific product, but rather the single most effective technique for insulating a greenhouse covered with standard film. By using two layers of plastic and a small inflation blower, you create a 4- to 8-inch bubble of air that surrounds your entire structure. This captive air pocket is a fantastic insulator.

The benefits are immediate and profound. A double-layer inflated greenhouse can reduce heating costs by 30-50%. The trapped air acts as a buffer, dramatically slowing heat loss. It also makes the structure more rigid against wind, and the pocket of air helps shed snow more effectively than a single layer. Condensation is also significantly reduced.

Setting it up requires a blower kit and some extra hardware, like a special lock channel to hold both layers of plastic. But the investment is minimal compared to the annual savings in propane or electricity. For any grower in a climate with freezing temperatures, running a single layer of film on a heated house is like leaving a window open all winter.

Ultimately, the best greenhouse film is the one that aligns with your specific goal. Are you simply trying to protect dormant plants, grow hardy greens with minimal heat, or maintain a warm environment for tender crops all winter long? Define your mission first, and the right choice—from a standard 6 mil film to an advanced bubble insulator—will become clear.