Monday, March 5, 2012

How to Build a Cold Frame


Cold frames, sun boxes, and hot beds are relatively inexpensive and provide a good environment for growing. You can:
  • Start cool weather plant seeds outdoors 6-8 weeks before the last frost
  • Extend your growing season
  • Harden off seedlings you started indoors
  • Shelter plants from ice, snow and treacherous winter winds
  • Use to compost, thus generate warmth to turn cold frames into hot beds
  • And, you can incubate cuttings
The top 12 winter cold frame crops are:
  • Arugula
  • Broccoli
  • Beets
  • Cabbage
  • Chard
  • Chinese cabbage
  • Green onion
  • Kale
  • Lettuce
  • Mustard
  • Radish
  • Spinach
  • Kale
This cold frame was build using nearly all salvaged building materials. I did have to purchase the wood and the retired window (from a thrift shop), but I already had the other supplies.


Step 1:  Gather Materials
●    Discarded wooden window
●    Scrap pieces of wood (long enough for each side)
●    Screws/ nails
●    Hinges
●    Tools (saw/jigsaw, drill, hammer, nails/screws, measuring tape, pencil, paint, brush/small roller)

Step 2:  Measure
●    Measure window dimensions
●    Measure wood to match windows dimensions

Step 3: Cut wood for frame
●    Cut along pre-measured lines 

Step 4: Assemble frame
●    Form a box with the 4 pieces of wood that have been cut.
●    Prior to nailing/screwing, place the window on top of box, to be certain your wood is cut in the proper dimensions.
●    Fasten each side together with nails/screws.

Step 5: Assemble window lid
●    Place window on frame to create a lid.
●    Fasten hinges to base and window (using screws).

Windows are attached in a way that suits the type of window it is.
Attach the hinge in a location that is easiest to access the box.

Step 6: Paint
●    This is not a mandatory step, but it helps the box to endure weathering.

Give it two coats and slop it on. You can give it a happy color.

Step 6: Put the cold frame to use!
●    Place on prepared ground in a sunny location.
●    Harvest and enjoy!

I selected sturdy wood, but a thinner piece would have been easier to manage.

Some Tips
  • Keep an inexpensive thermometer in a shaded spot inside the frame for quick reference. A bright spring day can heat a cold frame to as warm as 100 degrees. Prop open or remove the cover as necessary to prevent overheating.
  • Don't forget to water your plants. If it rains, leave the lid open.
  • On cold nights, especially when frost is predicted, cover the box with burlap, old quilts, or leaves to keep it warm inside.
There are no-standard-sized cold frames, so anything goes - as you may recall from this particular post.

"For as the earth bringeth forth her bud, and as the garden causeth the things that are sown in it to spring forth; so the Lord GOD will cause righteousness and praise to spring forth before all the nations." Isa 61:11

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