When building your first greenhouse, one of the challenges you will be faced with is figuring out how to attach plastic to the greenhouse frame. Over the years, I’ve tried a lot of different techniques for securing plastic sheeting in a greenhouse, and I’m excited to share them with you. There are some very cheap DIY ideas that work for one season and some that are more expensive but are good for a few years. Depending on your frame material and design and the thickness of the plastic, some methods are more appropriate than others. Let’s take a look.
As a greenhouse owner, I know how important it is to properly attach plastic. Not only does it protect your structure from high winds, but it also helps regulate the temperature and humidity inside the greenhouse.
1. DIY Garden Hose Clamps
DIY garden hose clamps work well with small caterpillar tunnels and hoop houses. Simply take a piece of old hose, cut the hose lengthwise, and use it as a clamp to affix the plastic to the hoop. This maybe be the cheapest and the easiest method that works well for a single season. You can slice the hose using a simple utility knife or kitchen scissors.
2. Batten Tape
Another cheap way for attaching plastic covers to wooden greenhouse frames is using batten tape. Please note – we’re talking about non-adhesive vinyl or woven polypropylene tape. It’s not to be mistaken for double-sided adhesive tape.
From my experience, batten tape works perfectly for holding down plastic to greenhouse doors and vents. I know this is an affordable and easy method. But personally, I would not recommend using batten tape to secure the entire greenhouse cover. The tape is designed to attach the poly film to a wood frame using staples which makes it a permanent attachment. If you need to uncover your greenhouse you won’t be able to do it.
Watch this video by Griswold Family Farms to learn how to staple batten tape correctly.
3. DIY PVC Snap Clamps
Using PVC clamps to attach plastic film to a greenhouse frame is one of my favorite methods. Clamps can be DIY-ed or obtained online. When choosing to DIY your clamps, you may need to attempt making cutouts in several different sizes to determine which size cutout fits best. Make sure that it takes an effort to snap the clamps onto hoops. Also, you want to smooth the inside edges of the cutout to avoid puncturing the plastic.
If you don’t feel comfortable cutting and making your own clamps from a pipe, you could obtain pre-made PVC clamps online (see image above), for just a few dollars. You’ll get the advantage of having rounded edges that lower the possibility of puncturing the plastic. Also, because these clamps are made specifically to secure poly film over a pipe, they have reinforced edges that provide additional strength and comfort, making them easier to remove without damaging the film.
These PVC greenhouse clamps are ideal for securing plastic without using adhesives and are versatile enough to be used in cold frames, row covers, hoop tunnels, and large greenhouses. However, they can be challenging to snap on and remove.
To overcome this issue, try a DIY solution like the snap-in PVC pipe clamp (see image above). This design, which involves two parts, can be screwed to a wood frame and snapped in place. Watch this cool video by ghog63 to get a better idea. I love the idea!
Finally, if you prefer a more comfortable, easy-on-your-hands option that requires no DIY work, I recommend trying the Fixed Film Clips. These clips, which I found at Walmart, are quite comfortable to snap on and off.
It’s really cool how the folks at Kathi Dunphy Watercolors worked as a team to tighten the rope around their tall and long greenhouse. It does take two people to make it work.
The rope is a simple but somewhat pricier option for attaching plastic to a greenhouse. Of course, it depends on the size of the greenhouse, but in this case, judging by the image below, the rope was the most cost-effective solution. The designers of this greenhouse had to provide special hook-ups to hold the rope in place – see those metal sticks on the bottom.
If you’re going to use this idea, I recommend the type of rope that does not stretch and withstands the elements. Braided Nylon Rope comes to mind, the one used for securing boats.
5. Rope with Grommets
Instead of dealing with the challenge of adding metal hook-ups to the frame, you can securely attach plastic to the greenhouse frame using a combination of rope and grommets. This method involves creating holes in the plastic using grommets, which allows you to thread the rope through them and tie it tightly to the frame. For a large size greenhouse, this could be a very effective approach that requires less rope and saves you money.
When using metal grommets on plastic film, it’s important to attach them correctly to prevent tearing. You want to apply strong adhesive tape on both sides of the plastic before driving the grommets through. For best results, use Gorilla Tape or Contractor’s Duct Tape. This method works best with heavier, thicker plastic and requires an Eyelet Hole Punch Set. Check out this video for detailed instructions on how to install grommets.
6. Wood Lathe
I have successfully used wood lathes for attaching plastic to my greenhouse. This method is suitable for a wood frame greenhouse. It won’t work on a metal hoop or PVC pipe frame greenhouse unless you build a wooden bottom frame.
Using wood lathes and heavy-grade plastic, I have gotten three years out of the plastic covering on my greenhouse. It has stood up to wind, rain, and snow well.
To make this method very affordable, you can DIY the wood strips on the table saw by ripping a couple of 2x4s into 1/4-inch thick strips.
I prefer to attach my PVC hoops to the inside of the bottom wooden frame, as this provides a continuous and unobstructed outside surface. I also leave some extra film on the sides. To secure the plastic in place, I create long lathes, wrap the plastic around them, and then use screws to secure them. This method helps to keep the plastic tight.
7. Tarp Clips
If you’re building a small hoop tunnel from metal fencing, you can secure plastic edges with tarp clips. You can find tarp clips in hardware stores or online.
Wrap the plastic around your fencing mesh, then clip it over the mesh and secure the clips. You can apply clips over the entire greenhouse or only in certain spots, as long as the plastic is kept taut.
8. Spring Locks
Here’s another easy way to keep the plastic in place over a small greenhouse tunnel. Use Nylon Spring Clamps, which are basically woodworking clamps. The image above shows you exactly how to do it.
9. Poly Lock Channel with Wiggle Wire
To attach plastic to very large greenhouses, the Poly Lock (Polylock) Channel and Spring (Wiggle) Wire are often used. This is a bit more expensive method but it allows you to quickly attach or remove the cover, and it provides a more secure attachment.
A channel lock system is basically a spring lock system. It consists of a series of channels that are attached to the frame of the greenhouse. The channels hold the plastic in place with wiggle wire and create a tight seal.
Here are the steps to install this system. Attach the lock channel to the frame of your greenhouse, then pull the plastic cover over the frame and press it into the channel. Begin inserting the wiggle wire into the channel with light force. The wiggle wire is quite flexible, so you can insert it into the channel one wave at a time until its entire length is locked in place.
This is one of my favorite methods in areas of high wind. It lets you easily replace the plastic as needed or tighten it if there is any sag.
10. Use Weights
Using simple weight to secure the plastic in place is an option that has been around for years. You can use mulch, dirt, rocks, bricks, or any other method to hold the plastic in place along the base of the greenhouse. Check out these three examples above and below, to get ideas.
Using cement bags.