Installing Greenhouse Plastic

Polyethylene plastic is popular cover option for greenhouse structures. It is a great option for farmers looking to use a structure for season extension. A good quality polyethylene greenhouse plastic should last you at least 4 years even in high UV environments when installed properly.

When selecting a plastic greenhouse covering you should select a thickness of at least 6 mil. The polyethylene film should also have a UV stabilizer built in.

Please do yourself a favor and don't buy cheap polyethylene film from the big box stores. These plastics lack UV stabilizers and will begin to break down from sun exposure. The plastic begins to shred and flake creating a huge mess that will need to head to a landfill after one season.

The size of your greenhouse film is determined by the length and width of the growing structure. You must also account for the total length of the pipes you are using to complete a hoop, and also your end walls. If you plan to do roll-up sides account for extra plastic. (approx. 4')

Check out: How to Determine the Size of Greenhouse Plastic You Need

Installing greenhouse film over your hoop house for the first time is where most of the questions come from when people contact our tech line at Bootstrap Farmer. We can honestly say that no one has ever called to tell us it was harder than they believed it would be.

We recommend starting the projects with a team of 3-4 people. Limited experience is required to help install the greenhouse plastic.

Keeping a good level head and only work with the piece in front of you, focusing on one foot at a time, is all you can do. You’ll find that once you get going you really don’t have a chance to stop. When you work in the proper order it all really comes together on it’s own.

It is a good idea to have a couple of pieces wood or paint roller handles on the inside of the structure to help nudge the plastic over the top of the hoops. Keep a step ladder ready for the end wall you will start on first. Some people like to tape cross connectors, hoop seams, and hardware to prevent premature wearing out of plastic. Duct tape works well for this. For an even tighter wrap we recommend using electrical tape for this step.

Begin by unfolding or unrolling your plastic lengthwise along the hoop house. You will know which side faces down (the anti-condensate side) as you will be able to read the labels from the inside of the hoop house

Covering a hoop house is best done in the morning when winds haven’t picked up yet. It’s easier to start on the side working into prevailing wind.

As you begin lifting the plastic over any breeze will help open up the plastic. If you work against the wind the plastic will be pushed onto the ribs making the job way more difficult than it needs to be.

Ideally two people will each grab a corner of the plastic on the ends and begin lifting over the hoops. This plastic can take significant tugs so do not be afraid to pull when needed. Be mindful of snagging on corners, boards, or hardware. This will cause rips.

If you have other helpers you can position them on the endwalls on the side of the film where it being unrolling from and help unroll/fold to give the pullers slack.

The plastic, when fully rolled out, will drape down on both sides and down both endwalls with at least 2’ all around the ground.

Begin at the top of an endwall and work down one side to the ground and then top to bottom again on the other side. Then move your ladder to the opposite endwall. With help, pull the plastic as tight as you can toward you and begin securing the film into the channel top to bottom and side to side.

Next, move to one of the long sides and begin securing the film into the lock channel with spring wire at the hip board. Once the plastic is secure along the length of one side, move to the opposite long side. While pulling down as tight as you can, secure the plastic with spring wire. After completion, you will be able to see where you can retighten the plastic by removing a section of spring wire and pulling from the bottom.

Once you are happy with the top, you can move onto the rollup side's installation or if foregoing the rollups, secure plastic to the baseboards.

Note: We will get to the end walls in the next post. A lot of folks ask us why the baseboard needs lock channel and spring wire if you are using roll up sides.

For one, it gives you the option to fully seal off your roll up sides with spring wire during a significant storm event or during the winter. Second, it gives you options to secure insect netting.

Note: insect netting needs to be installed before plastic goes on. And remember, more than one layer can fit into a lock channel.

For roll up sides you will wrap at least 1’ of greenhouse film around ¾ EMT down the length of the greenhouse. Feel free to cut off any excess from the bottom past 12”. Once the plastic is secured to the crank end, you may find that hand rolling the non-crank end as you roll the sides up and down assists in alignment. Once you are satisfied with that, roll the side walls down to the baseboard to begin trimming for the end wall.

Check out the next post for details on how to cover your endwalls.