Greenhouse Covering Materials Comparison – Glass, Polycarbonate, Polyethylene, Fiberglass, Acrylic and Vinyl

There are a variety of materials that can be used to cover a greenhouse today. With the current explosion of interest from both commercial farmers and backyard gardeners, the options for materials are constantly expanding. Greenhouse covering material includes:

polyethylene greenhouse covering

2-Layer Polyethylene Covering Later Patched w/ UV-Resistant Greenhouse Tape – You Never Know What May Damage Your Covering! Photo Courtesy: Photofarmer @Flickr

  • Glass
  • Polycarbonate (rigid panels or flexible rolls)
  • Polyethylene Plastic film
  • Polyethylene Panels (semi rigid panels or flexible rolls)
  • Fiberglass (rigid panels or flexible rolls)
  • Acrylic (rigid panels)
  • Vinyl

Since we had already decided on using PVC pipe for constructing our greenhouse, we would not be using any solid panel type material to cover the greenhouse, but we still estimate the cost to cover a small greenhouse ( 5 X 10 foot base 4 – 5 feet tall) below for each greenhouse covering material for comparison purposes. We also estimated the cost to cover a typical sized hobby greenhouse (10 x 10 foot base 8 feet tall). Keep in mind, these costs are for the covering material only. Any clamps, fasteners or furring strips would cost extra.

Glass is the Traditional “True Greenhouse” Covering Material

Glass has been the traditional greenhouse covering material. Chances are, the first glass greenhouse you saw years ago was made from hundreds of glass panels. Glass requires a very costly and sturdy structural system, but if constructed well, can last for at least 30 years and and clean glass always allows good light transmission. The main problem with glass is that is a poor insulator unless you use double or triple panes. Glass is also difficult and expensive to replace if broken.

A small A-frame greenhouse with a 5 X 10 feet base, standing only 4 – 5 feet tall would require between 114 – 137 square feet of surface area to cover. We looked up the price for two thicknesses (3/16 and 1/4 inch) for both annealed and tempered glass and found it quoted at between $5.78  to $8.44 per square foot.  Even if we could find glass for $4.00 per square foot, the cost for the glass alone to cover a small greenhouse would range between $457 – $1155. The glass for a normal hobby-sized greenhouse (10 X 10 feet base; 8 feet high;420 square feet of glass) would cost between $1680 to over $3600. You can quickly see why other materials are being used to cover greenhouses.

Polycarbonate Greenhouse Panels and Rolls

polycarbonate greenhouse panels

Single vs Double vs Triple Layer Wall Polycarbonate Panels. Photo courtesy of Colorado State University Cooperative Ext.

Polycarbonate is a very strong and light-weight material. Panels made for outdoor use have UV treatments that help prevent yellowing and deterioration from sunlight and are guaranteed for about 10 years. Brand names of polycarbonate panels include Dynaglas, Lexan, HighLine, Sun-tuf, Tuffak and Zelux. Polycarbonate panels are available in various thicknesses from 0.03 inch (0.79mm) to 1/2 inch (12.7mm)

  • Corrugated Polycarbonate Panels – rigid panels – single wall construction – cost $4.71 per linear foot (50 inches wide)
  • Polycarbonate Panels – rigid panels – twin wall construction with air space in between for added insulation – cost $51 for one 4 x 8 foot panel 6mm thick
  • Polycarbonate Panels – rigid panels – triple wall construction for additional insulation – cost $117 for one 4 x 8 feet panel 16mm thick
  • Polycarbonate Rolls – flexible sheeting – twin wall construction with air space in between added insulation -cost $6.17 per linear foot -rolls are 49 inch wide)

The Polycarbonate prices and cost estimates have been updated. The cost for covering the very small A-Frame greenhouse is much more economical using polycarbonate panels. The cost would range between $204-$255 for 6mm twin wall panels and between$468-$555 for 16mm triple wall panels.  The flexible twin wall sheeting would cost slightly about the same,  but would require a solid frame centered on 49 inches. A 10 x 10 foot hobby greenhouse would cost about $1600 to cover with the 16mm triple wall panels.

Acrylic Greenhouse Coverings

double wall acrylic greenhouse covering

Double Wall Acrylic Panel

Most people are familiar with acrylic skylights  and other “Plexi-glass” materials – (other Brand names include: Acrylite, Lucite, Optix, Polycast and Aristech) acrylic is very strong for snow, strong winds and even hail impacts, but very specific attachment requirement due to expansion and contraction. Acrylic is also very expensive, but can last 20 years, so one manufacturer claims it is cost effective over the long run, especially in commercial greenhouses where heating costs can be reduced up to 30%.  Though described as rigid panels, acrylic panels are flexible enough to be molded over shallow arcs. Acrylic panels are available in several options:

  • Single Layer Acrylic Panels -  Cost is about $90 for one 41 inch by 8 foot panel (corrugated clear)
  • Twin Acrylic Panels – air space in between panels for insulation – Cost is about $108 for one 47.25 inch by 8 foot panel (8 mm thick)
  • Triple Acrylic Panels – more air space, more insulation
  • Quad Acrylic Panels – most air space, most insulation
  • Non Drip Acrylic Panels – one side treated to prevent buildup of condensation, which increases light penetration and reduces damage to small plants from dripping water
  • UV Blocking Acrylic Panels – to protect UV sensitive materials inside the greenhouse

The cost for covering the very small 5 x 10 foot A-Frame is with acrylic panels is about the same cost as glass. Because the single layer we found listed is made in an unusual width (41 inches), it is about the same cost as the twin acrylic panels that are produced in 47 1/4 inch widths. The cost to cover the small A-Frame would would range between $432-$540 and the cost to cover a 10 x 10 foot hobby greenhouse would be $1440 – $1512. No doubt, the triple panels,  quad panels and UV blocking panels would be more expensive, but the products must be fairly new, because we could not find any online price quotes.

Polyethylene Plastic Greenhouse Coverings

polyethylene plastic greenhouse covering

Polyethylene Plastic Sheeting

As we have learned, all plastic coverings are not created equal. Choosing the Right Greenhouse film (AKA agricultural plastic, poly-film and greenhouse plastic).

  • Utility Grade (4 and 6 mil) polyethylene plastic  – will last one season exposed to sunlight – do not attempt to use for two seasons – available at most hardware stores – Cost for 10 x 25 ft roll is about $20.00
  • UV protection – Protects plastic film from Sunlight – guaranteed to last 4 years – Cost for 12 x 25 ft = $39.00 (6mm thick)
  • Thermal protection – Reflects IR back into greenhouse – claims to cut heating costs 15- 30% and to maintain higher temperatures at night if you don’t heat – Cost $92 for 12 x 55 ft
  • Anti condensation – condensation attached to film can reduce sunlight, also reduces dripping onto plants
  • Protection from heat – Opaque to reduce light transmission to 55% – Cost for 16 x 55 ft = $120

Polyethylene is the least expensive covering for a greenhouse. One 12 x 25 ft roll will cover the small 5 x 10 foot A-Frame two times, so it will cost about $10 to cover with utility grade plastic each year. It would cost about $39 to cover the A-Frame plastic greenhouse with UV protected polyethylene and even if it only lasted 3 years instead of 4, that would average $13 per year. The thermal rolls I was quoted are longer, so one roll would cover the A-Frame greenhouse at least three times, so $92 would last for 9 to 12 years, or $7.67 -$10.22 per year.

A 10 x 10 x 8 foot hobby polyethylene greenhouse could also be covered with one 12 x 55 ft roll of thermal protected polyethylene for about $92 and still have about 40% of the roll left over.

Polyethylene Panel Greenhouse Coverings

Polyethylene can also be made into panels, usually with a twin wall construction with air space for insulation in between – can be used to construct greenhouse as rigid panels or can be semi-flexible and be fitted to shallow arches. UV protected and some are guaranteed to last 8 years. Solexx is a brand name.

  • 3 mm flexible rolls with UV protection- Costs $6 per foot for 49 inch wide panels
  • 5 mm flexible rolls UV protection – Costs $8 per foot for 49 inch wide panels

The small 5 x 10 foot A-Frame would cost between about $180 and $280 to cover with flexible polyethylene panels depending upon whether we used 3 or 5 mm material and also depending upon the greenhouse being 4 or 5 feet high. That cost would average between $22.50 to $40 per year if the flexible polyethylene material would last 7 or 8 years. It would cost about $630 -$840 to cover a 10 x 10 x 8 foot hobby greenhouse.

Fiberglass Greenhouse Coverings

fiberglass greenhouse covering

Corrugated Fiberglass

Fiberglass is opaque, but lets about as much light into the greenhouse as glass does, and may allow more light in when the sun is at low angles because very little light is reflected. Seems as most manufacturers offer a 10 year guarantee against yellowing and structural failure. Seems as though fiberglass panels in the past would begin to  deteriorate on the top and expose fibers that would trap dirt. This would block sunlight and require washing and re-sealing.

  • Rigid corrugated panels – cost $72 for one 5 oz, 52 inch x 8 ft panel
  • Flexible rolls – cost $335 for 4 ft X 50 ft roll

It would require six fiberglass panels to cover the small 5 x 10 foot A-Frame greenhouse if it needed to be over 3 feet tall and would cost about $342.  It would require at least 14 fiberglass panels to cover a 10 x 10 x 8 foot hobby greenhouse and cost a little more than $1000. The A-Frame greenhouse could be covered with one roll of flexible fiberglass at a cost of $335 with almost half of the roll left over. A hobby greenhouse would require three rolls of flexible fiberglass at a cost of about $1000, but would have most of one roll left over.

Vinyl Greenhouse Coverings

Vinyl covering materials are primarily for used for a clear “showroom” quality look. Users are advised by the manufacturer to use only on the ends of the greenhouse so customers could have a nice, clear view of facilities. Not intended for use as covering for the top of the greenhouse. The clear vinyl “siding” is supposed to last about 4 years and costs $130 for 54 inch by 50 ft roll of clear film 16mm thick.

We have no intention of using vinyl, but just in case someone else is interested, the cost to cover the 4 sides of a a 10 x 10 x 8 foot tall hobby greenhouse would be $280 for two 50 ft. rolls. The roof would still have to be covered with another material.

Our Choice for a first time Greenhouse Covering

polyethylene greenhouse plastic

We Used 6mm Polyethylene Plastic For 2 Seasons

Our choice for a material to cover the A-Frame hoop house (greenhouse) for the first two seasons was the simplest cheapest material. We used a utility grade (6mm) polyethylene plastic. It works well with the PVC Pipe structure and is clamped to the PVC pipe with simple homemade clamps cut from short sections of PVC pipe. If you use polyethylene plastic that is not UV treated, do not try to use it for a second season. It may look OK at the end of your first season, but it will disintegrate before you make it through the second season, and it is nearly impossible to pick up all the plastic fragments. We still plan to use the same polyethylene plastic again this year, because we still have enough left over to cover the greenhouse again. Next time, we plan on using a buy a UV and IR protected sheeting because it will be more economical and less wasteful in the long term and our tomatoes and peppers could benefit from some additional thermal help on our cold nights.

After two growing seasons, the plastic sheeting held by homemade clamps have worked very well. When fastened correctly and completely closed, the plastic sheeting has even held up to wind gusts of 70 mph, but on an other occasion, when the greenhouse was  partially opened for ventilation (and only partially fastened), the plastic sheeting was blown loose by an approaching storm. The A-frame shaped hoop house also allows the plastic to shed snow without any damage.

Have a look at our --> Greenhouse Plans - Small & Large
Or, For Raised Bed Gardening --> Raised Garden Bed Plans

Q: What greenhouse covering material are you considering? Please comment below. You may also want to look at our Greenhouse Building Materials page that discusses the pros and cons of different types of materials for the frame.

Comments

  1. Hello,
    I recently read the article at http://www.homemadehints.com/greenhouse-covering-materials-comparison/ I’m very curious where you got the pricing on the rigid polycarbonate panels. The reason I ask is because its only a fraction of what i’ve been finding.

    Thanks,
    Tom

    • Homemade Hints says:

      Tom: We can no longer find those prices either. The cheapest source we found at the time the article was published is no longer available. We knew this was going to be a problem with publishing prices and then trying to keep them current, but will adjust the current prices for greenhouse polycarbonate panels ASAP.

      • No worries, I wasn’t able to tell when the article was published only saw the copyright at the bottom of the page so I figured it was at most a year old based on that. Just thought I would ask because I would LOVE to find prices like to build my commercial greenhouse lol.

      • I just came across this great information! It appears the pricing for polycarbonate panels has been updated from a few weeks ago. I would appreciate if you could mention the brand and the vendor offering the updated pricing. Btw, is the pricing quoted by the sheet without a minimum order, or for bulk/tier orders? I ask because I usually have to replace a panel or two a year to my existing houses though this year I am adding another house and will need to purchase more than two panels.
        Thank you!

        • Homemade Hints says:

          The Best prices we quoted for polycarbonate were from online vendors (brands unknown). Do online search for growerssupply, greenhousemegastore and advancegreenhouses. Also check farmtek. Check with the vendors for minimum orders and shipping.

          Adding another greenhouse? Sounds like you are seriously into greenhouse gardening… If you don’t mind sharing… How many greenhouses do you have? Is this for a business or a hobby? and why do 1 or 2 panels need to be replaced each year? Thanks

  2. Interesting discussion. I used a plastic “drop cloth” from a painting project. The plastic only lasted one year. It is a small green house 2×4 and 5 ft tall. The insulated panels look interesting but sort of expensive. Is the insulated panel the best ?

    • Hi John: We also still use “drop cloth” type plastic for our greenhouses, but we hate the fact that most of that plastic can only be used for one season, but have not been able to justify the extra cost for UV protected plastic sheeting.

      Which is best? Complicated answer and depends upon what your limiting factors are. A small greenhouse like yours will not cost too much either way.

      Our biggest problem during the middle of the growing season is cool/cold night time temperatures. We get plenty of heat during the day, so increasing the insulation to hold heat during the night is more important than trapping solar heat during the day. We would benefit from using double or triple wall polyethylene panels on the sides and then covering the greenhouse at night with landscape fabric or a tarp to hold the heat through the night. Biggest problem for that is I am the automation. I will have to cover in the evening and uncover in the morning.

      We are considering a hybrid solution for our greenhouse. By that, I mean a more permanent type of UV protected covering for the sides and the door, but still use simple plastic sheeting for the top. I have no doubt that polycarbonate, fiberglass or UV polyethylene sheeting panels will hold up there, which will justify the extra cost.

      The roof on our large greenhouse design holds up to serious wind, but would have to be re-enforced to handle the snow load we get here. So we will continue to remove the roof at the end of the growing season. If the roof has to be removed anyway, the cheapest cover still makes sense.The labor to remove and/or replace sheeting on a small greenhouse is small. Obviously, time and labor has to be considered for a large greenhouse.

  3. Steve Nelson says:

    I read somewhere else about using vinyl only on the ends. Have you found out why the manufacturers suggest against using it on the roof?

    • I think what they mean to say is that vinyl is a good choice for the ends of a greenhouse where a clear view is important, such as a commercial operation wanting a clear view for customers, not that vinyl can’t be used on the roof. Growerssupply recommends that vinyl can be used for “utility doors, panels on existing buildings, canopies or awnings”. I hope this helps.

Comments, Opinions, Questions?

*