Best-selling author and gardener Lorene Edwards Forkner presents us with her DIY cold frame to protect her vegetable patch from chilly weather and extend her gardening season.
She says, “Cold frames are devices to protect your tender vegetables from wet, chilly weather. They are a godsend in cool climates when you’re itching to plant and Mother Nature thinks winter is not quite over yet.”
This tutorial will guide you through the process of building your DIY cold frame using IKEA materials, ensuring your plants stay warm and cozy.
Materials Needed
- IKEA GORM shelving components (HEJNE or similar sturdy wood pieces)
- 4-foot lengths of upright supports (wood or metal)
- Rigid sheets of styrofoam insulation
- 4.5 mil plastic sheeting
- Duct tape
- Barn red paint (or any outdoor paint for moisture protection)
- Screws and a screwdriver
- Saw (if cutting is needed)
How To Build A Simple DIY Cold Frame
Step 1: Build the Frame
1. Position the corner shelf pieces: Take your three-foot corner shelf pieces and lay them down with the longest side facing down and the slanted end facing forward.
2. Assemble the frame:
Screw the two corner shelf pieces at right angles, horizontally to two 4-foot lengths of upright supports at the back of the frame to provide a brace at the top and bottom. Attach another four-foot length across the front to join the front edges of the frame.
Step 3: Paint for Protection
Once the frame is assembled, paint it with barn red or any outdoor paint to help it withstand moisture and soil contact. Allow the paint to dry completely.
Step 4: Insulate the Frame
“I know what you’re thinking,” Lorene adds, “this is the draftiest cold frame in the history of cultivated gardening.” At this stage, these frames would actually make good shade structures to protect young seedlings in the high heat of summer in July and August when she is seeding fall crops. Without cooling shade, the tender sprouts and their shallow roots are destined to fry.
However, for the colder months, you need to insulate the cold frame.
1. Cut the styrofoam: Measure and cut the rigid sheets of styrofoam insulation into pieces that will line the inside of the frame. It’s best to cut them slightly larger so they fit snugly.
2. Secure the insulation: Use duct tape to seal the raw edges of the styrofoam and ensure it stays in place. And ta-da! A fully insulated DIY cold frame.
Step 5: Add the Plastic Covering
1. Cut the plastic sheeting: Measure and cut the 4.5 mil plastic sheeting to the width of the frame and long enough to extend beyond the front.
2. Double the plastic: For extra protection against the cold, consider doubling the plastic sheeting to trap more heat, if necessary for your weather conditions.
3. Attach the plastic: Reinforce the edges of the plastic with duct tape and staple it to another four-foot length of wood. This will act as the back support for the plastic cover.
Step 6: Create a Ventilation System
The plastic cover can be rolled out to cover the box, partially removed for ventilation, or completely rolled up and secured at the back for maximum exposure to sunlight.
Step 7: Prepare for Planting
Fill the cold frame with rich soil, amended with compost and organic material to boost fertility and drainage. This is the perfect environment for starting seeds or protecting young plants from cold weather.
To capture the available light and heat, site the frame where it will receive full sun between 9 am and 3 pm with the long axis of the structure oriented east-west.
Step 8: Monitor Conditions
Keep an eye on the temperature and humidity inside the cold frame. Adjust the plastic cover as needed to ensure your plants are getting enough light and ventilation.
The addition of a 6- to 8-inch layer of horse, chicken, or rabbit manure turns the cold frame into a “hotbed” warming the soil considerably as the manure ages, a boon in cold climates.
“I was supremely excited to discover that these sturdy, light-weight boxes can also be stacked to form double-height frames to house my peppers and basil this summer; it really is quite ridiculous how cold it can remain around here until the 4th of July!” says Lorene. “I love that these DIY cold frames were really cheap to construct. I know my shivering plants will appreciate their snug new clubhouse.”
Happy gardening!