Build a Straw Bale Cold Frame

Cool fall and winter nights can be a disaster for your plants if you’re not prepared. To protect your plants from the seasonal dips in temperatures, build a cold frame with straw bales. It’s a great way to care for plants in the winter without breaking the bank.

1. Determine your space needs. Group the plants you want to protect, and measure the space that you need; length by width by height. Be sure to allow space in between the containers to give them some breathing room, and so you have room to tend to them.

2. Find your location. Cold frames are traditionally constructed backed up to a building for insulation. Choose a south or west wall to provide your plants with the best sun exposure during the short dark days of winter. The combination of solar heat, plus the insulating properties of the building and straw bale walls are the keys to successfully caring for your plants.

3. Find your materials. With your measurements in mind, purchase enough straw bales to build the three walls (the building provides the fourth wall) at the height you need to accommodate your plants. Just line ‘em up and stack ‘em. It’s easiest to have your plants in place while building, rather than fitting them in later. Heavy, translucent plastic is best for the top, and you can secure it in between the last two bales in the walls. Your local home improvement center will have a selection of plastic to choose from. Many cold frames have tops that angle out from the back wall at about 45 degrees to increase the surface area for solar heating, but if it’s not convenient to attach the plastic to the building, just tuck it between the bales and the building. Remember you will need to open it up for watering, so make allowances for that.

Come spring, store your bales for next year, use it as mulch for the garden or spread it on your compost pile.