DIY Cold Frame Using Old Windows

The Little DIY Cold Frame that Thought it Was a Greenhouse

Plans for an easy-to-make cold frame from old windows and how to keep your cold frame warm during winter.

Imagine the disappointment…through your entire, albeit short, existence…you’ve been lauded as a ‘Greenhouse’. There’s a certain cache to ‘Greenhouse’…it’s lofty and it’s a structure that serious gardeners all over the world aspire for…it’s right up there with ‘Conservatory’. But then, as a result of a few queries on the googler, you realize that you are not a ‘Greenhouse’, you are, in fact, really a ‘cold frame’. Hmmm…a ‘cold frame’, and a ‘DIY cold frame’ at that.

I guess I should have known the difference, I’m sure many of you in the colder climes surely know the difference…but all along I’ve been calling my newest build a ‘Greenhouse’, when in fact, it’s a Cold Frame. The difference between the two is simple, a greenhouse is heated while a cold frame is not. The difference is significant, but for my needs, this little DIY cold frame that thinks it’s a greenhouse suits the bill perfectly.

So, you may or may not remember that I’ve started a little Meyer Lemon Grove. And by ‘little’ I mean…well…4 baby Meyer Lemon ‘trees’.

And if I’m perfectly honest here, we’re talking ‘saplings’, just barely out of the seedling stage.

But I’m a little protective of these little guys…

I mean, I started them from the very beginning.

I was gifted a lovely, luscious Meyer Lemon by a girlfriend last Christmas; and not just any Meyer Lemon. This lemon was from her very own tree! What a truly lovely, personal and thoughtful gift! So, with this treasured Meyer Lemon, I made this Fig Conserve and then saved the seeds, with the hopes of starting my very own Meyer Lemon Grove.

I’ve conceded that my Greenhouse is actually a Cold Frame, don’t ask me to concede that I don’t have a Meyer Lemon Grove…that’s too much for one day.

So, these are my babies in February of this year…all sprouted and growing!

And now look at them! I am giddy with how well they are growing, like a proud mama!

So, now that I’ve nursed my babies from the very beginning…through droughts and hurricanes…I’m just a little invested in them.

(True Confession: Before the recent hurricane hit, I put my Meyer Lemon Grove under our deck to keep them safe from the wind and the rain. But, when we couldn’t get home for a week after the hurricane, I started to worry that they were dying under the deck. So, I actually…yes…this is the confession…reached out to friends who had stayed in town to go by my house and check on my Meyer Lemons…in the midst of all the Hurricane cleanup. Yup…I did that.)

This means that I needed to come up with a plan for the upcoming winter; our last winter was so bitterly cold, not at all suitable for my burgeoning Meyer Lemon Grove.

So, what’s a Lemon Farmer to do…

Well…of course, I needed a build a “Greenhouse”…I mean to DIY a “Cold Frame” for my mini-grove! And I’ll be able to get my basil and other tender crops outside a little earlier this spring…double perks!!

So, I headed to our local Architectural Salvage store and bought 4 old windows…2 sets of the exact same size.

They were dirty, and chippy, and looking for a purpose other than sitting on a shelf. It is a noble journey to be transformed from a dusty, old window to a much more regal DIY cold frame. 

We then hightailed it to the hardware store and purchased a 4′ by 8′ sheet of plywood and some hinges, came home and built this fantastic greenhouse….er, cold frame.  I’ve got to be honest…it really was a quick project.

What Materials We Used to Build our DIY Cold Frame:

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• Our cold frame measures 41″ by 45″
• 4 windows, our were 28″ by 33″.  If you are using old windows, make sure the paint is Lead-Free.  Use a test like this to determine whether or not the paint has lead in it.
• 3 hinges
• 1 piece of 4′ by 8′, 1/4″ thick  plywood
• Drill with screw bit or screwdriver
• Screws for hinges
• Hammer
• Nails
• Primer, Paint, Polyurethane

We get many of our building supplies at Home Depot. They have a wonderful program by which you can order here online and then pick-up at your nearest store within hours or at your convenience. In addition to building materials, they have an extensive selection of power tools and a power tool rental program if buying is not an option for you.

Without a handy set of “cold frame” plans, we set about figuring out how to build a DIY cold frame from these old windows.  

How we Made our DIY Cold Frame:

• Without a doubt, this project was made easier with 2 sets of hands.
• With the plywood on the floor, we set the windows up on the plywood in the size we wanted the finished Cold Frame to be.

  

Once we had it how we wanted it…we traced the outline of the windows on the plywood. Mark your outline on the outside of the window. You want the plywood to cover all the edges of the windows. It wasn’t perfectly symmetrical as one window on the roof is offset such that we could hinge it to the other one; one roof window is secured permanently, while the other is hinged.  You can see that in these pics.

• I would HIGHLY recommend priming and sealing your plywood side panels before you cut them. Also, seal the bottom of the plywood that will be on the ground and the part of the exposed window frame that is hinged with the polyurethane.  We had to do this after the Cold Frame was built and realized it would be much easier to do it beforehand. You can then touch up the cut sides easily after you cut the wood.
• We cut out 2 side pieces based on the outline. We cut the original one and then used that as the guide to cut the second one.
• We then nailed the plywood sides of the Cold Frame to the windows, making sure all our edges were squared up.

• Turned it on its side and nailed the other side to the windows.

  

• Then we nailed the stationary roof window to both sides.
• Once the 3 windows were secured to the 2 sides, we hinged the final window to the stationary window.
• Assuming you primed and painted before you nailed everything together, you are done!

• Put your greenhouse, I mean cold frame in a sunny spot such that the window side will receive sun throughout the day.

Since we are in the Southeast and don’t get the prolonged cold and freezing weather of some of you, I’m pretty confident I can keep my lemons in the cold frame all winter. However, if it looks like we are in for a prolonged, bitterly cold period, I will run an extension cord to it and place an outdoor spotlight like this with a 60 W bulb in it. For what it’s worth, LED bulbs don’t put off quite as much heat as incandescent bulbs, so you would want to stick with incandescent for this task.

(At which point I can call it a Greenhouse again?)

I might also experiment with filled water bottles painted black which will absorb the sun’s heat during the day, keeping the air in the cold frame warmer at night.

And if it seems necessary, I will also cover the cold frame with a blanket or tarp, ensuring that it stays even warmer.

If you are in colder climates, you can use your cold frame to extend your fall and spring growing seasons, as well as grow your winter greens like spinach, kale, etc…protecting them from the harsher elements.  In fact, a cold frame will create a little microclimate a zone and a half warmer than your actual location.

OK, so if you want to make a little DIY Cold Frame that thinks it’s a Greenhouse, bookmark this page or pin the following image!

Thanks for making my day by SHARING!!