Cold Frame with Double Walls, Protective Screen AND Automatic Openers Let the sunshine in and keep the critters out!

Share your love of DIY:   
Compost Tumbler with A-Frame Base

Cold Frames are a tried and true method of extending the gardening season, and in many places, allow year-round growth. These double layer cold frames have double side walls and twin-wall polycarbonate lids for insulation. What really sets these apart from most designs is having protective screens AND automatic openers. Download a FREE Plans & Cutlist PDF that shows you how to build Automatic Opener Pockets, that are screened and house the automatic openers.  

Scales with automatic opener and screening roll

With most cold frames, you have to choose between automatic openers and protective screens…

Scales with automatic opener and roll of protective screen

With most cold frames, you have to choose between automatic openers and protective screens…

The problem:

Cold frames are simple structures and share many of the same benefits as full-size passive greenhouses. One key difference over their larger brethren is their small size. This means the sun can heat the smaller air mass faster, but without proper ventilation, it can rapidly become much too hot and harm your plants! 

Both greenhouses and cold frames need ventilation to keep the plants healthy and the temperatures inside them stable. Very few plants do well with extremes in temperatures over a short period of time. 

Many DIY cold frames depend on manual ventilation, consisting of someone propping open the frames and then closing them down at night or when the temperatures dip.

The problem here is twofold: 

  1. Opening the frames allows wildlife in to eat all the tender, tasty goodness inside. Flying pests and insects have no barriers to prevent them from “pestifying” the plants. Those poor young, defenseless plants!
  2. Keeping up with the ever changing ventilation needs inside the frame is a monumental task. In our climate, we often have wild shifts in temperatures throughout the day. We had a recent swing of 70 degrees F in a single day. Constantly monitoring and modifying the ventilation would be a full-time, crazy-making job.

A simple solution would be to add protective screening to the frames and install automatic openers. Great idea! But, the two are mutually exclusive. The screens interfere with the ability of the openers to function. 

Bummer. What is a gardener to do?


The solution:

The solution lies in creating a screened pocket for the automatic opener to allow it to function properly. With the screening in place and an opener, all the critters stay out while the sunshine pours in! The best of both worlds!

The walls have double layers of 3.5 mil plastic sheeting to provide for much better insulation than a single layer could. The plastic is a great balance between durability, and the ability to transmit light. 

Finally, the twin-wall polycarbonate sheeting for the lid is nearly indestructible and passes almost as much light as glass. Perfect protection for heavy rain, snow and hail.

Pretty awesome right? And it’s not very difficult to do!

Plans with a cutlist for these pockets are available in the store, and FREE.

The video shows how to make these super-duty cold frames and make for a great DIY project! As always, feel free to ask questions, leave comments, tips, variations, and add YOUR project to the discussion below.

Monster truck trying to crush cold frame

The twin-wall polycarbonate lids on these cold frames are strong and let in almost as much light as glass

Monster truck attempting to flatten cold frame

The twin-wall polycarbonate lids on these cold frames are strong and let in almost as much light as glass

Plans & Cutlist for Automatic Opener Pocket

New for this project – Now you can download Plans and a Cutlist for the Automatic Opener Pocket.
Extend your growing season with this mini greenhouse!

Note: These screened automatic opener pockets have been designed to work with the specific openers that I used. The tolerances are snug, and openers come in a wide variety of sizes and configurations, so others may not work in these pockets. 

I spent a LOT of time researching the available openers before choosing these, and they have performed flawlessly. I highly recommend them!

Summary of Steps:

  1. Determine the structure of the frame
  2. Wrap the sides with plastic sheeting
  3. Make the automatic opener pocket
  4. Prepare the lid for the opener
  5. Prepare and install the opener
  6. Attach the lid and screen
  7. Add the finishing touches and mount the frame
  8. Enjoy your much longer growing season!

Show us your cold frame!  Now you can share photos in the comments below! 

Disclosure: Some of the links below are affiliate links. At no extra cost to you, I may earn a small commission on items bought using them. These are the same recommendations I would make regardless of any compensation. For products that I have older versions of, I recommend the items that I would replace them with if I were buying them new. 

Resources for Cold Frame with Automatic Openers

These are the tools I used in this project. You do not need all of them, so feel free to substitute with tools you have available.

Automatic Vent Openers

From Amazon
Keep consistent temperatures

10mm Polycarbonate Panels 2’x4′ 2-pack

From Amazon
Nearly indestructible, admits nearly as much light as glass

4 mil Plastic Sheeting

From Amazon
Great compromise between cost and durability

BetterVue Screen Kit

From Amazon
Keep those pests out!

Minwax Polyurethane

From Amazon
Protect the wooden upper frame

Rubber Weatherseal

From Amazon
Seal the drafts to keep the heat in

Cordless Electric 6 in 1 Stapler

From Amazon
Cordless convenience for driving lots of staples

1-1/4″ Electric Brad Nailer

From Amazon
For assembling wood frames. Alternative to air compressor/pneumatic nailer

3 Gallon 1/3 HP Air Compressor

From Amazon
Light duty compressor, perfect for brad nailers, tires, etc.

18GA Pneumatic Brad Nailer

From Amazon
Inexpensive alternative if air compressor available

Manual Staple Gun

From Amazon
Inexpensive manual stapler

Plexiglass Cutter

From Amazon
Used for cutting the polycarbonate panels

There are more DIY projects in the works, so stay tuned to Uncharted DIY. Feel free to comment, post photos of your cold frames or ask questions about this project.

Uncharted DIY is for DIY enthusiasts tackling uncommon projects, utilizing common tools and often on a limited budget

Uncharted DIY is for DIY enthusiasts tackling uncommon projects, utilizing common tools and often on a limited budget