Introduction: Build a Cold Frame With Recycled Materials

Cold frame gardening is a simple way to extend your harvest season, allowing for fresh crops year-round. The structure consists of a bottomless box that sits on the soil and a glass "light". 
Construction is easy--the cold frame can be made using salvaged wood and old storm windows. 

Step 1: Gather Materials

 - Find a light. In this case, we used an old storm window measuring approximately 70'' x 26''. The light should not exceed 4' in width, to make harvesting an easy reach. 
- Find scrap wood that will fit your light.
Note that the frame can be made of other materials such as concrete blocks, straw bales, etc.
 
Tools and Hardware you will need:
- Sawhorses 
- Hammer
- Screwdriver
- Saw (handsaw would work, but we used a circular)
- Measuring Tape
- Builder's square
- Pencil
- Hinges (we used a 4" strap hinge)
- Handles 
- Something to prop the light open to harvest and vent (we used a curtain rod)

Step 2: Measure and Cut

- Measure the exact dimensions of your light. 
- Measure and mark the wood to fit your light exactly. 
- The frame should slope towards the south (for maximum solar gain in the winter). Therefore, the back of the frame should be at least 4" higher than the front. 
- Cut and label your pieces. Remember that the two sides should have an angled top. 

Step 3: Assembly of Frame

- With all of the pieces laid out, begin to screw them together. 
- Use a square and corner brackets to make sure the pieces meet at right angles. 
- Reinforce corners with nails for added stability. 

Step 4: Attach the Light

- Place light on top of frame, making sure that it fits to perfection. 
- Attach the light with several heavy-duty hinges, spaced evenly. 

Step 5: Finishing Touches

- Add handles to the sides of the frame for easy transport.
- Add additional handle on light (if necessary) for trouble-free opening and closing. 
- Add prop for ventilation and simple harvesting. This can be a hydraulic arm, stick, or, in our case, a curtain rod. Ideally, the prop should serve multiple heights. 

Step 6: Put It to Use

- Find a good, sunny location for your cold frame.
- Prepare the soil and get to planting!

Here are some suggestions for winter cold frame crops:
- Arugula
- Carrot
- Lettuce
- Radish
- Parsley
- Scallion
- Endive
- Mache 
- Spinach
- Swiss Chard 

Remember, crops vary depending upon your location (and the amount of sunlight you get in the winter months.) 


We would like to credit the book "Four-Season Harvest" by Eliot Coleman for being a wonderful and informative reference. 

Comments

author
tim_n (author)2010-04-20

I've built a similar project myself.  I used ex-scaffolding boards, sealed the rough cut edges with a sealant to make sure slugs can't get in.  I used a dumpster dived shower door.

I've got a pic, but unfortunately my old unsupported version of IE won't let me post it on instructables, but you can view it here

Mine is perminantly placed though and has weed supressant membrane coving the bottom and two inches of gravel.  The gravel traps the heat during the day giving a slow release throughout the night.

I can then seed pots on the gravel and be assured that they won't have too much of a problem unless it gets particularly hot.  In the south UK last year I melted plant pots in it during the summer!

author
NullLifeException (author)2010-04-16

 Great instructable.  I'd just like to make a comment about building walls out of straw bales.  While this is great insulation, straw bales exposed to the elements become wet.  Wet straw bales are a breeding ground for bacteria and fungus, resulting in mold.  If you have a problem with mold (ie. you have asthma) don't use straw bales.  I wouldn't be too worried about the mold spreading to the plants, but it is certainly possible.