How to Build a Cold Frame Garden Bed

I have always wanted to learn about how to build and grow in a cold frame garden bed.

Last year that dream became a reality when Mr. Wonderful added the top frame on one of our regular garden raised beds. Let me show you how he did it.

Here is what our raised beds look like.

I wish I had all the room in the world like my sweet friend Marie at the Lazy W but I absolutely LOVE our raised beds!

By the way, in case you’re wondering -the red structure on the sides and overhead is for when the heat hits in Oklahoma in July through September. We attach 50-50 garden shade fabric over the top to help prevent scorching and help ease the temperatures.

We also use it to tie twine up to because we grow our tomatoes vertically (click here to read about that!).

Here in Oklahoma, our winters can be pretty mild and lettuce has been known to kind of hang tough and live through them in the garden, but plenty of times, the cold stunts them and they just stop. So I got this idea that if I could have a cold frame, or a somewhat insulated covered garden bed, that I could have lettuce and greens or even carrots, radishes and other cold weather crops all winter.

I was right! (This photo was taken at the end of January).

I’ve already showed you how we grow lettuce (click here for the tutorial).

Now let me show you how Mr. Wonderful added a lid to our existing raised bed to make a cold frame!

First off he put an angled board on each side so that the rain or moisture runoff would slope downward and not accumulate on top.

Then he put a straight board at the back to keep that elevation up.

Then he built the top frame as a rectangle that fit the bed. Next he stretched heavy duty plastic fabric across the top of this rectangle (bought from the tractor supply) and stapled it on.  He then screwed narrow pieces of wood around it with 2 cross pieces for stability.

He did NOT put a piece across the front edge however.

He attached the top with four hinges at the back.

And at the front, he put a turn knob with wood to hold it closed.

We just rotate it to open.

The great thing about the bed is we can open it on nice sunny days.

But we can keep it closed on cold days or close it at night when the temperatures drop too low.

And we only need to water it about once a week, because the water condensates on the lid and drips back down.

I direct sowed seed into and we now have a bumper lettuce crop going!

I’ve even planted more kale – look at those babies I need to thin out!

So there you have it! Our inexpensive cold frame lid. It’ll bring us greens all year around!

We are excited enough about it that we think we’ll do another one next fall!