Cold Frame: the treasure box

Cold frame vegetables, (c) Copyright 2007, Jade Leone Blackwater

It may not look like much, but whenever I see my cold frame I salivate and think about dinner.  A cold frame is a tool for extending your harvest through the cold months by protecting plants from wind while capturing a maximum amount of the low-winter sun to keep the plants warm.

Cold frame vegetables, (c) Copyright 2007, Jade Leone Blackwater

We built this coldframe in October 2006, and it has been feeding us ever since.  Our design is based on what we learned in Eliot Coleman’s book Four Season Harvest.  (We’ll talk more about this book in the future.)  Cold frame designs can be modified to fit your available space and materials.

Rather than use old storm windows for glass “lights”, we chose to use PVC plastic on our cold frame.  Despite our mixed feelings about PVC, I’m always glad we made this choice whenever I see our husky take a flying leap on top of the cold frame when he’s feeling “defiant.”

Cold frame vegetables, (c) Copyright 2007 Jade Leone Blackwater

This year the cold frame is filled with the end-of-summer jalapeños, carrots, and a few stray onions, as well as fresh rows of oak leaf lettuce, mizuna mustard greens, and slow-bolt cilantro.  As we explore nutrition, food, cooking, and gardening at AppleJade, you’ll be seeing a lot of our cold frame – and its bounty.

Do you have questions about cold frames?  Contact me with your questions, comments, and ideas any time, and I will try to address them in future posts.

11 Responses

  1. yummy! simple and functional. did you work from a plan?

  2. Fotokew, greetings and welcome! Yes indeed, we did work from a plan. We took a look at the pictures in Coleman’s book, and then drew up our own design on graph paper. From there we made our materials list. It turned out to be worth the time to sketch out our design first – that made the process much smoother when it came time to put everything together. Perhaps I can find the sketches, and add them in my next post? 🙂

  3. I am wanting to start winter gardening and hope to find various SIMPLE designs. Two questions:
    1. It is Late November here in Ohio. Is it too late to start some lettuce and spinache in a cold frame for winter harvest?
    2. Is it toxic to use treated lumber to outline my glass frame? What kind of wood should I use if not wolmanized?

  4. Hello Greg,

    If you’re looking for simple, the cold frame is just your cup of tea. You can build one much smaller than what I have here, and still have a nice, bushy crop of greens to feed you and your family.

    In response to your questions:

    1. My answer to this question is “maybe.” It’s not too cold for lettuce and spinach to grow – however, you may have a tough time getting the seeds to germinate. One way to solve this is to start the seeds indoors (let me know if you want tips on this, and I’ll blog about it next). Once those sprouts come up, transplant them to the cold frame. Just be aware that because it’s cold, they’re going to grow slowly until springtime. Cilantro, arugula, and radishes are also EXCELLENT growers at this time of year.

    2. I do not recommend using treated lumber for your cold frame. Since these foods go straight to your table, it’s safer to use non-treated lumber. Now, naturally that wood is going to break down easier over time, especially since it’s in direct contact with the soil. If you want to slow that process, you could spend some extra time and care to create a sort of gravel “trough” around the perimeter upon which to seat the cold frame. However, we have had ours in the ground for over a year now, and the wood is holding up just fine. I’m sure over time, that wood will decay, but so far, so good!

    Those are both great questions, I’m glad you stopped by. If I can be of further help, please don’t hestitate to ask!

    Happy gardening and good health,

  5. I’m also interested in more details about your cold frame because I would like my husband to build one.

    How tall should it be? Are your plants in soil or in pots? How do you know when to open the top to let in air? Is it set on concrete, gravel, soil or a piece of wood?

    How are the pieces on the top attached? Are they more practical than just a sheet of plastic that can be rolled back?
    Thanks, Martha in Muskogee OK USA zone 7

  6. Hi Martha! Clearly I need a nice post with all the details of the cold frame.

    The quick answers are:

    The cold frame only needs to be about 6-8 inches tall, but it can be taller.

    My plants are growing directly in the soil, and I open the cold frame for air whenever it’s warm enough (on cool days, that’s around 11am when there’s sun to warm the plants, on really cold days I keep it closed).

    The cold frame is not set in anything – the wooden box is completely stand-alone, just set right on the ground. The top is attached by hinges, and swings open like a doors.

    As I said, I definitely need a complete post with all the details. I’ll write more in December to provide more complete answers to your questions. If you are eager to get started, I definitely suggest you get your hands on a copy of the book I mentioned by Eliot Coleman – it’s all there!

    Happy planting, and thanks for visiting. Your questions are very helpful for me to get a post together.


  7. […] Philadelphia had a cold weekend, and here in Chester County we saw bits of sleet, snow, and freezing rain.  Our temperatures remained around 30 degrees (Fahrenheit) on Sunday, but our plants stayed cozy in the cold frame. […]

  8. […] in Chester County, Pennsylvania will soon see enough warmth to begin germinating seeds in the cold frame.  Once that happens, I’ll be sowing carrots, radishes, cilantro (coriander) lettuce, spinach, […]

  9. […] I just finished sowing onions, spinach, radishes, and carrots in the open spaces of my cold frame (a great way to enjoy a sunrise).  As you can see the cilantro, mizuna mustard, and assorted […]

  10. […] was kind enough to include a link to our cold frame discussions here at AppleJade.  While I am not a strict vegetarian, I enjoy vegetarian and vegan cuisine, and […]

  11. […] they can be replanted with the cold season vegetables.  My favorite cold weather crops for the cold frame include cilantro, lettuce, spinach, and other greens, as well as radishes, onions, and carrots.  […]

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