I'm trying to build a DIY greenhouse and have a question about the plastic sheeting.

I see that no one is using clear plastic - it's almost always translucent. Is that on purpose or just that the very clear plastic sheet is not available on large scale.

I was planning to purchase this 3.5 mil clear plastic sheet for my DIY greenhouse (to be built on 1st floor patio (5ft x 5ft x 5ft)) in Cupertino, California (Hardiness Zones 10a, 10b and 9b)

Does this plastic sheeting looks good or should I find something really clear plastic sheet like in this photo?

Any ideas & feedback much appreciated.


  • I am flummoxed. Seriously, why oh why do you want or need a greenhouse? You live in paradise for growing plants out of doors. You should get bunch of beautiful pots...lots of different sizes but all pots should look related. Turn pots upside down to place a pot for height. Group pots. Plant a grouping of plants so that the plants are related as well. The rule is: you get more for your money more PUNCH if you use just one spectacular plant. The other plants will be framed and highlighted by your skeleton planting. I am thinking Orange Sedge as a foundation plant (pull straight up ....
    – stormy
    Oct 22, 2019 at 10:02
  • ...gather the grass together into one big pony tail, straight up and using sharp bypass pruners or sharp scissors, give it a hair cut. Take off the last couple of inches and let the ponytail go. Beautiful. The less you remove the better...mix with red crocosmia,images.homedepot-static.com/productImages/… This will be your height for your pots. Next you would figure what medium plants/flowers to plant in some of the pots, not all. Use only potting soil in ALL POTS. Need to know what environment.
    – stormy
    Oct 22, 2019 at 10:09

3 Answers 3


With greenhouse plastic there are some issues to keep in mind. First, if you are considering a longer term installation then UV light will quickly shatter regular plastic. UV resistant plastics are available. Even then your max lifetime is about 4 years. The second issue is abrasion. With expansion and contraction of the plastic sheet the plastic cover is almost always loose and responds to wind and even light gusts. This rubs the plastic against the frame. Again, for a longer term project a thickness of 6 mil is much preferred; 3.5 mil is very flimsy. Translucent may well be good enough for the plants; if perfect clarity is highest on your priority list, then go for the clearest you can find but be prepared to replace it frequently.

  • 2
    You use mm where you should use mil. Note that 6 mm is 236 mil. 6 mil is 0.1524 mm
    – Dan D.
    Sep 5, 2018 at 11:12
  • 1
    Correction to units applied thanks to Dan for observation. Sep 5, 2018 at 11:16
  • Ah thanks. I was trying to quote how they sell, so folks could connect better with the links i shared. But point noted. Thank you :) Sep 5, 2018 at 15:28
  • This project is temporary, not for many years as i rent the place and can potentially move out in a few years. Happy to build a new one then. Sep 5, 2018 at 15:31

I used clear plastic, but it became translucent in one or two years.

On many climate, clear plastic (and clear glass) is too much in summer. Translucent is often a good compromise for winter and summer seasons.

Translucent has the advantage that it diffuse the light, so there is less problem on putting more dense crops (space in greenhouse is more restricted/expensive). I also think that we care much more about 'greenhouse effect' and not about amount of light (screening the outbound light and heat).

  • Thats a valid point. I'll go with the clear plastic sheeting which i mentioed in the links. Thanks Sep 5, 2018 at 15:33

Mayank I've used all kinds of plastics including the cheap stuff. I finally purchased the correct plastic for the skin of a greenhouse. This is warrantied for 4 years. The cheap stuff disintegrates within a year. It will fall apart in chunks or if you've got snow, your green house will implode.

The 'good' stuff has at least a 4 year warranty against UV damage. This is the minimum you want to purchase and use. The plastic you are considering isn't made for green house skins or any exterior application where the plastic is harmed by sun. The good skins are a bit opaque, not clear.

Installation of this plastic is another issue for longevity of the 'skin'. 4 years is very nice but still a short time. Installation is critical. You have to use 'padding' beneath the plastic above the structural members and then you fasten that plastic using proper screws with 'skirts', round gasket like things so the plastic doesn't tear. Make sure you know which side of the plastic you purchase that is meant for a greenhouse is supposed to be UP facing the exterior of the greenhouse.

Don't use the cheap stuff or you shall have to learn what we all had to learn the hard way. Just saying! Skinning a green house is a LOT of work. What kind of greenhouse do you have or are making? What zone do you live? Are you using the garden soil in place or are you doing pots? Will you have artificial lighting? Make sure you have big fans in place to run 24/7 during the season.

  • I'm in cupertino, california : on 1st floor, using potting mix soil. Needed to build a small 5ft x 5ft x 5ft greenhouse for my plants. Thanks for the detailed answer :) Sep 8, 2018 at 4:21
  • I just gave you a comment about WHY do you think you need a greenhouse in ZONE 10? Greenhouses are for the poor souls like little old me who chose to live with raw winters. You need to think of a pot grouping, not some greenhouse. Great chairs a little table but a grouping of pots at different heights. Great pots of different sizes, shapes but all related. Such as all metal pots (you might have to drill holes in the bottom of these pots). One is squat and square, another is tall and more narrow, another is turned over to support a pot at a much higher height...
    – stormy
    Oct 22, 2019 at 10:18

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