Cold Frames

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We had a really ROUGH winter this year.  Normally our winters here in Boise are pretty mild.  Most winters we only get a couple of snow falls during the entire winter.  This winter, however, we had record breaking snow falls.  I think we broke a couple of records in all of recorded history!  My kids had 6 snow days and probably should have had a couple more.  We had one storm that called for such extreme weather that we filled up our bathtub with water (just in case).  We also checked our emergency food and water supplies.  It was a doozy.

Needless to say, I’m very glad that spring is on it’s way and while it is not quite here yet, at least the mountains of snow are gone and the sun shows it’s beautiful head once in awhile!

Last fall, I made a few cold frames to see if I could extend my growing season.  I made them out of salvaged wood from an old fence we took down.  I more or less followed the building plans in Elliot Coleman’s book “The Four Season Harvest.”  If you want/need an online building plan, you can find one here.  The lids of my cold frames are covered with plastic sheeting, 6ml thick which you can find here.

(Update: After using this plastic for a couple of years, it became brittle from the sun and fell apart.  I am planning to replace it with a sheet of Plexiglas as a permanent solution but it is quite a bit more expensive than the 6ml plastic sheeting.  Just know that if you use this plastic sheeting, you will need to replace it every year or two)

Here is a picture of the cold frames and the hoop house in the background.  Both were experiments this year.

Other than going out one time (on one of the warmest winter days) to see if anything was still alive, I pretty much did nothing to these cold frames all winter long.  And they kindly kept my salad greens alive for me…no questions asked.

I think I’m in love!

Tips for using a cold frame:

• For fall/winter gardening, the plants need to be full grown before cold weather comes.  This means that you will need to start seeds in the summer or early fall, depending on the variety.
• Take the “days to harvest” number on your seed packet and count backward from your first frost date.  Add an extra week or two (to account for slower growth in the fall) and this will tell you when you need to plant in your cold frame.  Example: If you want to grow spinach in your cold frame and the days to harvest is 63 days and your first frost date is October 15th, you would count backward from October 15th approximately 70 days or so.  It does not have to be exact, just get a ball park date.  In this example, you would want to plant around August 15th.
• Depending on the variety, you may have to allow the seeds to germinate indoors and then plant them outside.  Some of the cooler weather crops may not germinate in the heat of the summer.  If you need more information on how, exactly to plant using a cold frame, you can check out this book by Caleb Warnock “Backyard Winter Gardening” or this book by Eliot Coleman “Four-Season Harvest: Organic Vegetables From Your Home Garden All Year Long”
• Plants will continue to need water while in the cold frame.  Maybe not in the middle of the winter, but certainly in the fall and spring.
• The cold frames will need to be ventilated (i.e. opened a small amount) on hot days so that the plants don’t wither or fry in the heat. For more details on this, check out Elliot Coleman’s book listed above.
• You can also use your cold frame in the spring to get a jump start on summer growing.  Use it like a mini greenhouse to start seedlings in…no more needing to harden them off before transplanting!!

I thought I would do a video to show you how the plants inside of the cold frames fared during the frigid weather.  All-in-all, I’m super happy with how they worked!  I couldn’t have asked for anything better.

Who knew you could have fresh salad, straight from the garden in February?!?  🙂

Enjoy the video!