Cold frames can be just the answer for those wanting to grow fresh veggies beyond the traditional growing seasons of their area.  Often called the poor man’s greenhouse – a well-built diy cold frame can keep fresh greens on the table nearly year around  – and at the very least – extend your season by a month on each end!

Our cold frame built form a pair of old window sashes and two pieces of 2 x 10 x 10' framing lumeber
Our diy cold frame built form a pair of old window sashes and two pieces of 2 x 10 x 10′ framing lumber

Cold frames can be used to grow cold-hardy crops like lettuce, kale and spinach. Even as the snow begins to pile up on the ground outside!

In addition, they are a great place for gardeners to start tomato and pepper seedlings in the spring. 

A cold frame is nothing more than a simple structure with four walls and a clear roof designed to let in the warming rays of daylight.  By nature – they heat up the soil during the day – and keep the plants protected from freezing and frosting temperatures during the cold nights.

The walls can be made from almost anything – wood, brick, stone or even straw or hay bales.  For the top – something as simple as thick clear plastic, plexiglass or glass will work perfect.  We built ours for about $20 from just two pieces of 2 x 10 x 10 framing lumber, a couple of old windows – and a few scrap hinges. 

cold frame
2 windows and a few pieces of 2×10 lumber is all you need a homemade cold frame

For our cold frame, we used a few old window sashes we had on hand – but you could just as easily make a wood frame with clear plastic sheeting for a top.  We just thought the windows made for a great looking piece – and hey – they were free 🙂 !

Our two windows measured  27 x 24” – so we built the frame at 54″x 24″ to hold the windows exactly.  This will be the perfect size to sow a fair amount of lettuce and keep us in salads for weeks at a time!

How To Build A DIY Cold Frame

A few quick cuts with the circular saw - and the cold frame was ready to put together
A few quick cuts with the circular saw – and the cold frame was ready to put together
Take one of the 21" side boards and make a cross-line to create your identical angle boards
Take one of the 21″ side boards and make a cross-line to create your identical angle boards
A quick cut and you have perfect matching angles
A quick cut and you have perfect matching angles
Simply screw together the bottom pieces to form the rectangle
Simply screw together the bottom pieces to form the rectangle

For our diy cold frame, we used a few old window sashes we had on hand – but you could just as easily make a wood frame with clear plastic sheeting for a top.  We just thought the windows made for a great looking piece – and hey – they were free 🙂 !

Our two windows measured  27 x 24” – so we built the frame at 54″x 24″ to hold the windows exactly.  This will be the perfect size to sow a fair amount of lettuce and keep us in salads for weeks at a time!

Materials :

(2) –  2 x 10 x 10’  regular framing lumber – untreated
(2) –  recycled window sashes  (be sure to use windows that have no lead paint)
(4) –  3” hinges
(24) – 3” exterior screws

If you do not have access to old windows for your top – you can create a frame from 2×2 framing lumber and plastic sheeting.

Step 1 – Cutting out the pieces

We cut (2) 54” length pieces from the first 2 x 10 x 10. From the second 2 x 10 x 10, we cut out one more 54” piece and (3) 21” pieces

We took (1) of the 21” pieces and drew a diagonal line from the top to the bottom of each end – making a perfect angle. We then cut it with a circular saw (you can use a table saw or jigsaw) to create two perfect angled end pieces for the windows to sit on.



Step 2 – Assembly

you can sink a screw at the front of the angle on each side to attach second row boards
you can sink a screw at the front of the angle on each side to attach second row boards

Assembly was simple – we screwed together (2) of the 54” sections between (2) of the 21” pieces.

We pre-drilled the ends to keep the wood from splitting.  The frame then measured 54 x 24″ when completed.

We then took the angled boards and mounted them to the sides by driving one screw in the bottom portion of each side (again, pre-drilling to keep the wood from splitting)

We then attached the back 54” board to the back of the angled boards with screws.

To secure the unit completely – we attached a strip inside in the back corner to hold the upper and bottom layers together.

At this point – you could keep it super simple and cover the top with a frame of clear plastic – or, if you are using old windows like we are – we attached the sash to the back of the wood frame with a few basic butt hinges. The cold frame is now ready to go!  Be sure keep an extra piece of wood nearby to prop the windows or top frame on warmer days and allow for venting.

You can attach windows with a few simple hinges - or a wood frame with a plastic top to cover your cold frame.
You can attach windows with a few simple hinges – or a wood frame with a plastic top to cover your cold frame.

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Happy Gardening!  Jim and Mary

14 thoughts on “How To Build Your Own DIY Cold Frame

  • November 10, 2016 at 8:30 am
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    I grow my own vegetables in a small way and would love to build myself a cold frame, however I live alone and am unable to use electrical tools (it simply is not safe for me to do this). Is there a simpler way to build something like this, without having to use these electrical tools and keep it very affordable?

    • November 10, 2016 at 8:34 am
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      Linda, you can use straw bales and plastic or glass on top to create a cold frame, even old windows on top will work

  • September 26, 2016 at 11:19 pm
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    Would this work in areas where the temperature drops to -40C (sometimes colder)?

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  • January 15, 2016 at 8:24 am
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    Please be careful using old wood window sashes. They could be painted or glass with lead paint or old putty that was made with lead. Test first with lead paint test kits found at good harwarestores.

  • April 7, 2014 at 7:08 am
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    Can you use pallets for garden raised beds?

    • April 7, 2014 at 7:50 am
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      Jenny – as long as they are untreated – they would work well.

  • March 26, 2014 at 2:12 pm
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    Could you install something like this over a raised bed, or would the soil get too cold because it’s above ground? We have an old patio door that I am determined to put to good use! Thank you for a helpful post!

    • March 26, 2014 at 8:54 pm
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      It can be done to help heat up the ground quicker and to help with preventing frost – it may not however provide the same thermal heat as if it was in the ground – hope that helps!

  • March 3, 2014 at 10:29 am
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    Can other vegetables be grown in these as well? Or are only greens viable? I love this idea and absolutely want to try it! 🙂

  • February 26, 2014 at 7:58 am
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    I’m an avid garage sale shopper and I watch for old shower doors, can sometimes pick them up for a dollar apiece. They are great for so many things, including converting part of my raised beds to a cold frame.

    I’m enjoying reading your blog and I love how inventive you are. Keep up the good work!

  • February 25, 2014 at 8:59 pm
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    I love this idea for when we move further north and can’t grow year-round. It’s so affordable to make one and have veggies through the winter. What a treat!

  • February 25, 2014 at 8:57 am
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    In 2008 we had a major ice storm in northern New England (no power for 11 cold December days!) and a huge pine tree came down and crushed our picnic table. Since the table had been made from untreated wood and I’d used a garden-friendly finish on it, I cut up the remains and built a coldframe I use to this day. The design is just like yours and like you, I used an old window sash (no lead paint) on top. I use the coldframe all summer long, too, for greens I want to keep out of the resident groundhog’s mouth. I took some small strips of wood and leftover screening and created a screen that will sit on top of the coldframe when the window sash is partially or fully open. Works like a charm! Love your blog and its many good ideas.

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