This project is excerpted from The New 5-Gallon Bucket Book: Ingenious DIY Projects, Hacks, and Upcyles by Chris Peterson, copyright 2021 Cool Springs Press. Used with permission. 
What You’ll Need
Tools
- Measuring tape
- Permanent marker, such as a Sharpie
- Level
- Compass or trammel
- Handsaw
- Cordless drill and bits
- Jigsaw or frameless hacksaw
- Scissors
Materials
- 5-gal. bucket with snug-fitting lid (white)
- 6-mil plastic sheeting
- Epoxy for plastic
- (2) 21/2” (6.4 cm) galvanized steel butt hinges
- Machine screws and bolts (to match
- the hinge holes)
- Analog stem thermometer
Time
45 minutes
Difficulty
Moderate
Expense
$
Cold frames make any garden more versatile. They are the cousin to the greenhouse, offering a great deal of flexibility to the gardener. The principle behind them is to create a temporary space for tender or overwintering plants where they can be safe from freezing temperatures—and incidentally protected from predators such as insects.
Cold frames are used anywhere the temperature regularly dips into freezing temperature over the winter months. Like all cold frames, this one can be propped open to allow for venting and to prevent plants from overheating.
The structure is used for a few different purposes. It provides a great way to overwinter plants that would not survive a harsh winter in your local climate. They can be left where they are planted and protected in that space (for this use, you’ll want to cut the bottom half of the bucket in half again, so that it can be pressed down into the soil around existing plantings).
More often the cold frame can be used to start plants early, before the soil and air temperature warm to seasonal temperatures. You can also use a cold frame as a transitional space, to harden off seedlings that you’ve started inside but that may be too tender for early spring temperatures.
No matter what purpose you use it for, the plastic will help insulate against cold temperatures in both the soil and air.
It is also plenty durable and can take a beating and still beuseful for years to come.
How You Make It
- Remove the bucket handle. With the lid securely attached, carefully measure and mark a cut line across the center of the lid. Use a level to extend the cut line down each side of the bucket and across the center of the bottom. Use a compass or trammel on the bottom and lid of the bucket to mark a centered circle on each. The circle should be about 91/2” (24.1 cm) in diameter on the lid and about 81/2” (21.6 cm) in diameter on the bottom.
- Use a handsaw to cut the bucket in half. Use a level as a straightedge to connect the two sides of the marked arcs on the bottom and lid of one bucket half, leaving about 1/2” (1.3 cm) margin between the cut line and cut edge. Drill an access hole and use a jigsaw or frameless hacksaw to cut out the half circles. These will be the end windows for the cold frame.
Chris Peterson - Measure and mark a 10″ × 16″ (25.4 × 40.6 cm) window in the bucket half with the end windows, centered across the body of the bucket. Note: A good shortcut for this is to cut out a 10″ × 16″ (25.4 × 40.6 cm) piece of stiff cardboard and use it as a template to mark the cutout.
- Drill an access hole and cut out the 10″ × 16″ (25.4 × 40.6 cm) window.
- Use the bucket end windows to mark 6-mil plastic sheeting for the windowpanes. Measure and mark the plastic for the main window. Use a scissors to cut out the windows, leaving 1/2” (1.3 cm) extra all the way around.
- Use plastic epoxy to glue the 6-mil plastic windowpanes in place on the inside of the bucket, covering the window openings.
Chris Peterson - Hold the two bucket halves together and mark one long side for the placement of the hinges. They should be centered about 6″ (15.2 cm) apart. Fasten the hinge leaves to one half with the machine screws and bolts, and then to the second half.
- Drill the hole for the stem thermometer in between two of the bucket top flanges. The stem should pass through the hole but be snug. Dig a concave hole for the bottom of the cold frame, set it into the ground, and fill the bottom half with soil, making sure the bottom half is sitting level. Plant the plants and close the top of the cold frame. Slide the thermometer in place.
Read more about cold frames—why you should use them, other ways to build them and more—here!
