Are you having difficulty finding durable greenhouse plastic?
I know it’s frustrating when your greenhouse cover fails mid-season. To help you avoid such issues, I put together this guide.
Inside, I detail several of the best greenhouse plastics and explain why you need them. I also discuss essential features and answer frequently asked questions about greenhouse plastic to assist in your purchasing decision.
Greenhouse Plastic Specs I Look For:
|Price||Needs To Be Balanced And Affordable|
|Fastener||Reinforced Edges And Holes|
Top 5 Best Greenhouse Plastics
Farm Plastic Supply 4 Year Clear Greenhouse – 6 Mil (12’W x 28’L)
Reasons To Buy
- Polyethylene plastic is lightweight and easy to install
- The tough material withstands freezes, heat, wind, and rain without tearing
- Features a UV inhibitor that prevents degradation of the material for years
- Range of sizes available to cover just about any greenhouse in one sheet
- Transparent film allows you to take full advantage of sunlight and heat to increase plant growth
Reasons To Avoid
- If your greenhouse frame is PVC, you will need to form a barrier before adding this film
- Hazy coating on new film reduces transparency but does wash off
The Farm Plastic Supply Clear Greenhouse Film is made of a durable, low-density polyethylene material that’s large enough to cover smaller greenhouses that need full sunlight exposure.
I like the additional UV inhibitor treatment on the film that protects against harsh UV light for four years, which means you can keep your greenhouse intact much longer than other brands of plastic sheeting.
On the downside, the material has a hazy white coating on the surface as you open it up. The substance does wash off shortly, and the plastic is clear.
The 6 MIL Farm Plastic Supply Clear Greenhouse Film is best for gardeners who want to get many years of use from their greenhouse before needing to replace the cladding. This plastic tops the list for its affordability and toughness against the elements.
Light Deprivation Greenhouse Cover 100% Blackout Film – 6 Mil (40′ x 25′)
Reasons To Buy
- White exterior is pleasant to look at while reflecting heat and sunlight
- Ample size can cover larger greenhouses with one-sheet
- Complete light blockage allows you to control plant development
- Watertight coverage helps stop greenhouse leaks
- Polyethylene plastic conforms nicely to the greenhouse shape without tearing
Reasons To Avoid
- Material feels thinner than the thickness on the label
- Large size makes it heavier and more difficult to install
The Light Deprivation Greenhouse Cover 100% Blackout Film by Farm Plastic Supply is the one to choose when you need to control the light reaching your plants.
I like the dual-color, with white on the outside to reflect sun and heat, while the black interior blocks out light. The waterproof plastic is reliable during rainstorms to keep water out of your greenhouse.
On the downside, the material is not breathable at all and completely blocks out light, which can cause a stuffy and dark greenhouse environment.
The Light Deprivation Greenhouse Cover 100% Blackout Film is best for gardeners who require full light blockage to control growth stages such as flowering. This product makes the top five for its durable poly material, large size, and effective sun-reflecting white exterior.
NAVADEAL Silver Reflective Mylar Film – Set of 6 (82″ x 47″)
Reasons To Buy
- Both sides of the material have the same finish and can reflect up to 95-percent of light
- Very affordable way to increase greenhouse warmth and light while reducing hot spots that can burn plants
- Individual sheets let you spot treat specific plants but can tape together when necessary to cover a wall or large area
- The mylar is PET coated to prevent surface corrosion, which extends use both inside and outside the greenhouse
Reasons To Avoid
- Individual sheets will need taping together to cover a large area
- Folds in the sheeting are permanent, which can be problematic for some users
- The material likes to “cling” to your skin, making installation difficult
The NAVADEAL Silver Mylar Foil Sheets help encourage plant growth by reflecting and diffusing light to areas of your greenhouse that need it.
I like the nearly four by seven-foot sheets that come in a set of six, so you can position the sheets where you need them most. The material is both puncture and tear-resistant, which means with proper care, it should last several seasons.
On the downside, the material is semi-transparent, which means it works best when you tape it to a solid surface or fold it in half to achieve full reflectivity. The film is also very thin and lightweight, which can make it difficult to position.
The NAVADEAL Silver Mylar Film Garden Greenhouse Covering Foil Sheets is ideal for gardeners on a budget looking to improve interior greenhouse light conditions. This product is a top choice for reflectiveness and value, with six sheets in the package.
Heavy Duty Clear Greenhouse Tarp – 10 mil (12′ x 24′)
Reasons To Buy
- Material is nearly double the thickness of other greenhouse plastic sheeting products
- Reinforced corners and edges increase strength, which reduces tears or fraying
- Material is waterproof and resists rot, for long-lasting use
- UV protection treatment keeps the integrity of the material intact under intense sun
Reasons To Avoid
- Tarp size and grommet placement may not work for all greenhouses
- Grommets can pull out of the plastic
- Not exactly clear, as the white interior mesh filters the sunlight
This Heavy Duty Clear Greenhouse Tarp by Watershed Innovations is a commercial-grade plastic sheeting option when long-lasting strength is necessary.
I like the many features this greenhouse plastic offers, such as UV coating on both sides, an interwoven mesh for additional durability, rope edging along all sides, and rust-free grommets for secure installation.
On the downside, the size of this plastic is restrictive. The location of grommets or edges may not line up with your greenhouse framing.
The Heavy Duty Clear Greenhouse Tarp is best as a cover in regions where you require heavy-duty protection from wind, rain, and sun. This greenhouse plastic makes our list for its additional mesh reinforcement and super thick material at a cost-effective price point.
Heavy-Duty Polyethylene Sheeting by ECOgardener – 6 Mil (10′ x 50′)
Reasons To Buy
- Large size is perfect for a variety of greenhouse needs
- The plastic cuts smoothly and evenly, which reduces waste
- White and black side are reversible for ideal control of lighting and heat condtions
- Thick material is easy to secure without tearing
- Plastic is treated with a UV protectant to extend longevity
Reasons To Avoid
- Material is flammable, which means you must keep grow lamps and other electrical items at a safe distance
- Unrolling the plastic to open it up fully can be a hassle
The Heavy Duty Polyethylene Sheeting by ECOgardener provides plenty of material to cover an average-size cold frame or be put to use inside the greenhouse for hydroponics or soil protection.
I like the strong poly film that is UV treated for long life. Use the white side to increase lighting inside grow rooms or face it outwards on your greenhouse frame to reflect the heat and light from the sun. Use the black side to control light exposure to force plant development.
On the downside, the material provides no ventilation, so use fans, vents, or windows to increase airflow. The plastic is also flammable, so use with caution around grow lights.
The 6 mil Heavy Duty Polyethylene Sheeting by ECOgardener is best for gardeners looking for a dual-purpose greenhouse plastic that can work as a cladding or for interior use in grow rooms or hydroponics. This product lands on the list for sheer durability and functionality at a reasonable price.
Do You Really Need Greenhouse Plastic?
Yes, greenhouse plastic is critical to combat weather conditions that can make year-round gardening impossible. The best part about going with plastic is the cost.
Solid cladding on greenhouses can run into the thousands of dollars, whereas plastic for even huge greenhouses may only cost a few hundred dollars.
Here’s a list of benefits of using greenhouse plastic:
- Blocks wind and rain that can destroy delicate plants
- Contains heat so you can grow plants in cold weather
- Allows sunshine, while keeping pests and harmful UV rays out
- Keeps out rain, so you can control water reaching your plants to stop root rot
- Is much safer and cheaper than glass or plexiglass when severe storms cause damage to the structure
- Lets you control how much light reaches your plants, to encourage germination, flowering, and fruit production
Growing plants year-round for personal use or profit is much more affordable and convenient when using greenhouse plastic to cover your frame.
Greenhouse Plastic Features To Consider
Before I get into essential features, do take a look at your structure.
Wooden frames may have sharp corners, nails, or screws that can tear greenhouse plastic if you don’t add protection over these areas.
Pressure-treated lumber and PVC piping both contain chemicals that can degrade plastic that comes in contact. Paint or cover these surfaces before cladding your structure to ensure the plastic lasts.
The material on your greenhouse has a huge impact on its function and stability. Most gardeners choose one of these three materials as cladding:
- Polyethylene sheeting – Utility grade plastic copolymer found at home improvement stores
- UV-treated Greenhouse or Agricultural polyethylene sheeting – Withstands degradation from constant sun exposure
- Polyvinyl plastic – Thick and UV treated, which extends lifespan significantly
Most gardeners find that using a thick polyethylene plastic with built-in UV protection ends up being budget-friendly yet lasts for two or so years before needing replacement.
Polyvinyl is very expensive and hard to find in large rolls, which makes this material less attractive for the average home gardener.
For single-season use, a plain utility-grade plastic from the hardware store can work and is the least expensive option.
Most greenhouse plastics are in thicknesses between 3 mil and 10 mil.
3 mil is the thinnest option and is rarely used outside of single-season greenhouse use as it stretches and tears easily.
6 mil is the standard thickness for most greenhouse plastic as the material is thick enough to pull taut and secure over a cold frame without ripping and withstands general weather conditions.
Any plastic above 6 mil will be sturdy and can even help maintain heat and keep its integrity during winters in regions with freezing temperatures.
For plants to achieve photosynthesis, sunlight must reach them, so the color of plastic plays an important role.
CLEAR – Clear greenhouse plastic allows the most light penetration but can sometimes cause hot spots in the interior where the light is more intense in one area every day.
WHITE – White plastic will allow plenty of light, but the color will diffuse the sun’s rays and spread the light and heat evenly across all the plants inside your greenhouse.
The softer light helps plants grow more uniformly as they aren’t “reaching” for one area of intense light. For tall plants and trees, white also prevents the top foliage from scorching.
BLACK – Black is also called light deprivation plastic, and its purpose is to cut off all sunlight to the plants, which can be necessary for some growing operations.
Most of this type of plastic has a white layer on one side to reflect the sun’s rays to assist in stopping light penetration.
A UV-stabilizer on your polyethylene or polyvinyl greenhouse plastic is crucial for a longer lifespan.
Intense sunlight deteriorates plastic quickly, leading to tears or crumbling of the material.
During manufacturing, workers mix in a UV stabilizer to protect the material from degradation caused by ultra-violet light. The stabilizer filters out the UV radiation as the sunlight passes through the material.
Green vs Clear vs White Greenhouse Plastic
Many people fail to consider the reason most greenhouse plastic is clear, while green and white are two other prevalent options.
The differences between them are:
GREEN – Looks aesthetically pleasing as it blends better with the landscape but reduces the intensity of light spectrums reaching the plants inside.
Green is tricky as the color naturally filters out both blue and red spectrums of light and about half of the PAR (photosynthetically active radiation) from the sun. Plants need blue light for growth and red light for flowering.
CLEAR – Allows the most sunlight, and therefore optimal photosynthesis action for the plants. Clear also allows in plenty of heat, which is beneficial when growing plants in colder months.
Clear is best for seed germination and starters that you plan to transplant outside as the full sun is necessary for sprouting and cell development.
WHITE – White diffuses light wonderfully, which avoids harsh direct light hitting only portions of the plants. The balance of light within the greenhouse encourages even foliage growth to all plants.
White is best for growing plants from seed to full maturity inside your greenhouse. The soft light diffusion prevents hot spots and plants from getting leggy from straining to reach a more intense area of sunlight.
Greenhouse Plastic FAQs
What Kind Of Plastic To Use For Greenhouse?
The best greenhouse plastic for home gardeners is polyethylene plastic with a UV barrier. This type of plastic is also known as “agricultural plastic,” as farmers use it for a myriad of uses. With the right thickness, you can expect the best results from this greenhouse plastic as it can withstand sun, rain, wind, and even small hail without tearing. The plastic is transparent, allowing plants to receive the sunlight they need to germinate and develop. White or a white/black combo are other colors that aid specific growing needs. Polyvinyl carbonate is an extremely durable option and can last many years, but it’s a costly and challenging material to work with.
How Thick Should Plastic Be For A Greenhouse?
The minimal thickness I suggest for even one season of greenhouse use would be six mil. For the average climate, this is durable enough to withstand rainstorms and winds without ripping. In milder climates, you can risk using a 4 mil plastic, but don’t expect the material to hold up to falling or flying branches or objects. If you cannot purchase UV stabilized agricultural/greenhouse plastic thicker than 6 mil, consider doubling up the material to increase strength.
How Long Will Greenhouse Plastic Last?
A non-UV-treated greenhouse plastic commonly sold in home improvement stores will typically last a season to a full year on your greenhouse barring severe weather events. Legitimate greenhouse plastics are UV treated. These plastics can last anywhere from two to five years on average. The small increase in price to upgrade to a UV-protected greenhouse plastic is well worth the additional longevity it provides. The last option for flexible plastic sheeting is UV-treated polyvinyl. This transparent material comes in thicknesses up to 20 mil and can last five or more.
I can’t live without my greenhouse and rely on quality plastic to keep it fully functioning season after season. I hope this guide provided you with the options and information necessary to find a perfect fit for your gardening needs.
When you use the best greenhouse plastic, you protect your plants while providing the ideal amount of light. The results are healthy and beautiful flowers, fruits, vegetables, and plants everyone can enjoy!