Planting in Cold Frames for Winter Harvest

I had my first crackling fire in the fireplace last night.  I was considering having it on the kitchen floor, but went with convention.  And safety.

By tomorrow there could be a scorching heat wave with a humidex of bathhouse.   You never can tell at this time of year.  The weather’s as unpredictable as the path of a butterfly.  Or the success of a Will Smith movie.

Which makes cold frames a bit of a struggle because you have to actually pay attention to them.  The beauty of the cold frame is that it’s pseudo-gardening.  There isn’t a lot of work with them in the cold months.  For the most part you just lift the lids and pick your lettuce or beets.  But at this time of year you have to be reallyyyyy careful about making sure you vent them properly otherwise you’ll end up with a big batch of cooked plants.  So unless you plan on also  throwing a glug of olive oil, salt, pepper and a toothpick into the frame, you have to make sure to keep an eye on the temperature in there.


Various Cold Frames


For Spring and Fall plants like beets, carrots and lettuce the temperature inside the cold frame shouldn’t get above 60 degrees.  So if the temperature outside is 40 degrees, you need to vent your glass lights.  If the temperature outside is about 50, you need to remove your glass lights.  Put them back on once it’s late afternoon and the sun isn’t beating down on them.  This will keep the frames warm throughout the evening and cooler night.

I planted 2 kinds of beets in August.  Early Wonder beets which really did grow twice as fast as the other variety I planted.
DSC 0821
I also planted Cylindrical beets, which instead of growing round, grow more like a carrot, without the tapering at the end.  So all of your beet slices will be the same size.

I also threw some carrots in there in August and low and behold they’ve been a success.  A HUGE success.  I’ll bet 10 of the 742 carrots I planted grew.   I really should write Mother Earth News about this carrot miracle.

And then yesterday, I built another cold frame so I could plant greens.  I ran out of wood so I scrounged around the house for anything I could build a square, 3 sided box out of.  I came up with some very old bricks and an ugly storm window frame.
Brick Cold Frame


This frame isn’t tilted like the other ones are, but since it’s made out of brick it will hopefully retain heat a little bit better.  This is all a crapshoot.  I actually have no idea how any of these coldframes are going to do.

Laura, from Cubit’s Organic Seeds sent me all the seeds one could ever need for planting fall and winter cold frame crops.
Seeds For Cold Frame


Anything you plant in a cold frame for fall growth takes much longer to grow because the conditions are cooler and there isn’t as much sun.  However, if you’re going to grow greens in a cold frame, you’re meant to harvest them when the leaves are only 3″ or so high so you won’t be waiting around for the plant to get to full mature size.

Mache is one of the best cold frame crops for this time of year.  Lettuces grow well too and can actually freeze solid and still be fine to eat. You just have to wait until they’ve thawed out again (by late morning) before you harvest them.  If you harvest them while frozen they’ll turn to icky mush.  But if you harvest them once they’ve naturally thawed they’ll be beautiful, crisp, baby lettuce leaves.  Even in January!

Baby greens seem to be able to withstand the freeze/thaw cycle but full sized plants do not.
Cold Frame Plantings For Winter

I was on the ball enough in August to get a few carrots and beets into the ground but there’s a lot more I could have planted if I’d had my act together.

At this time of year, if you do it *immediately* you can still be successful with  several things in your cold frames.  I say that with all the confidence of someone who has never done this.




Pay attention to your venting and you could be serving a baby green salad with radishes for your Christmas/Hannukah/Kwanza/end of December dinner.
Lights On Cold Frames


Don’t pay attention to your venting and you could find yourself face down in the dirt gnawing away at your sautéed beet greens.


  1. Kat - the other 1 says:

    Olive oil, salt, pepper, toothpick, check!
    When will this be ready? lol ;)

  2. Becky says:

    Since I only discovered your blog a couple of months ago, I am catching up on all your previous posts. (Plus, it beats washing a sink full of dishes.) Seriously though, how did that improvised brick cold frame work for you? I have a ton of bricks I use in the garden for various things all summer, but stack them up out of the way over the winter. It would be cool to use them for a cold frame. Thanks!

  3. Jana says:

    I love to stumble and I do it entirely often but I did so earlier this week and smack dab into your site.. Love at first site and I’m enjoying the hell out of your ramblings…

    Learn while you laugh has always been the best way for me and todays how-to is no exception. Particularily loved this addition by you listed below:

    “At this time of year, if you do it *immediately* you can still be successful with several things in your cold frames. I say that with all the confidence of someone who has never done this.”

    Genius! lol and fits me to a T… thanks so much for sharing your adventures as I’m totally diggin it ;)

    • Karen says:

      Well I’m happy you found my site Jana and even happier you stuck around. ~ karen!

    • Gertrude Wells says:

      when preparing your cold frame, what do you use for your medium. Store bought or home made compost and what are the lights that ou talk about.

      I am here in Southern New Jersey.

      • Jana says:

        Those are great questions Gertrude. I didn’t think to ask about the light area either.

        Karen? Will you please do the honors when ya can? ;)

      • Karen says:

        Hi Gertrude! The “lights” are how you refer to the glass or windows on top of the cold frame. :) So they aren’t actual lights. You don’t have to fill the cold frames up, you simply put them on top of your regular garden soil. (You may be thinking of a raised bed, which you would fill with soil. ~ karen!

  4. Carna says:

    Hi Karen,

    I stumbled across your blog through another article. Am delighted you are into cold frame gardening. I unfortunately live in a townhouse in northern California so my childhood and early adulthood gardens in cold upper peninsula Michigan are not an option. But we did used to do some of the cold frame crops. I wanted to recommend a book that I have had for a number of years; this guy and his wife actually traveled to France to get all the dirty secrets on awesome winter gardens. I usually wishfully look at the crop rotations and produce ideas when I am lamenting my lack of a yard. Four Season Harvest by Eliot Coleman. He actually made a homemade mobile greenhouse like cover that he moves around depending on the weather. Enjoy and good luck with your lovely garden!

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