TUTORIAL: Build your own cold frame - cheap, quick and easy

condensed from an earlier post: http://joyandjubilee.blogspot.com/2008/03/im-wearing-green-thumb-for-st-patricks.html

Materials:
Bricks (I think I used about 100 bricks... give or take)
window frame with glass intact
weed cloth
gravel or rocks
fill dirt
topsoil

Hints:
- I got the window from freecycle, and it came with a matching screen which will come in handy to keep squirrels and other rodents away from the vulnerable plants once the top comes off.

- The fill dirt came from my own yard, as did the rocks/gravel

- This kind of installation is perfect for decks and patios, as it can be disassembled easily - or simply used as a planter later in the season.

How-to:
Step 1: Choose your location. You'll want a mostly-sunny spot, but try to find a place that gets at least some shade during the day - otherwise, you run the risk of cooking your plants. If you are constructing this on a deck or raised surface, pick a spot with adequate support and planon making a smaller cold frame. You don't want your deck to collapse!

Step 2: Measure your window, and lay out one layer of bricks in a shape that matches the size and shape of your window. After the first layer is down, place the window on top to check the layout. Make sure that all edges of the window are centered over a brick edge - you don't want the window to overhang the brick edges.

Step 3: Start layering up your bricks. I planned for a smaller cold frame - about 30" x 30", and only about 14" of dirt. Since my area was to be small and shallow, I did not bother mortaring the bricks or supporting the walls in any way. If you are planning a large cold frame, you might considering staggering the bricks for stability (this requires cutting some bricks in half) or using rods to shore things up.

Step 4: Install the liner. After you get to a good depth (at least 12", I'd say), stop laying bricks and get your weed cloth. Most cloth comes on rolls about 36" wide. Cut strips of cloth to cover the entire bottom and sides of the coldframe. If you have to use more than one strip, make sure the strips of cloth overlap a few inches. Let the extra material hang over the sides of your frame for now...

Step 5: Rocks or gravel. Add a layer of rocks or gravel to cover the bottom of the cloth-lined frame. You could also use busted up old flower pots, broken chunks of brick, seashells. Anything to provide a drainage layer at the bottom.

Step 6: Fill dirt. Get fill dirt from somewhere - many people give it away (check freecycle or craigslist) or just dig some out of your own yard. Fill about halfway up with plain fill dirt. If you are feeling fancy, you could skip this step and just fill the whole thing with potting soil.

Step 7 : Potting soil. Dump in a thin layer of potting soil, and work it into the top of the fill dirt. Dump in the rest of your potting soil, up to your desired depth. Tamp down lightly.

Step 8: Finish the bricks. Trim the overhanging weed cloth so that it only overlaps to the middle of the top brick. Place at least another 2 layers of bricks along the entire frame, so that your seedlings and plants will have enough headroom to grow.

Step 9: Place the window flat on top of the frame... and you're done! Simply tilt the window up or remove and place to the side when you need to get into the frame. On sunny days, slide the window so that a crack of fresh air can get in, or just remove one of the corner bricks to let in some air - otherwise you might overheat the interior. Just put the brick back in place at night.

You can see photos here: http://www.flickr.com/photos/melaniejeanbrown/sets/72157623934475859/

Have fun! You can take this basic idea and fancy it up a multitude of ways...

~Melanie