For many people living in the Llano Estacado region, winters are slightly shorter and warmer than other parts of the country. That’s good news for folks who want to extend their garden growing season, and an excellent way to do that is with a cold frame. Easy to construct and maintain, cold frames are a valuable resource for gardeners who want to grow their favorite plants and vegetables all year long.
What is a cold frame?
A cold frame is just that – a frame that protects plants from colder weather. The frame also lets sunlight in so that plants can continue to grow. A cold frame allows you to grow winter seedlings and crops in many regions around the country despite cooler winter temperatures.
How cold frames work
The cold frame shelters your plants from cold winds, ice, and snow, and heats up the soil whenever the sun is shining. The soil inside the cold frame warms up much faster than the open ground, and many hardy vegetables can germinate in the 50-degree range. Once the seeds begin to grow inside the frame, the plants are surprisingly cold-resistant.
A word of caution: make sure that your cold frame has proper ventilation because your plants won’t thrive if the cold frame is allowed to overheat. It’s also important to add water when needed to keep the soil moist.
Ideal plants for cold frames
Cold frames are mostly used for frost-tolerant plants and vegetables since the plants inside will only be slightly warmer than the temperature outside when the sun isn’t shining. The following vegetables are easy to grow in cold frames during the late winter months:
You can also use your cold frame to grow spring transplants but be sure to bring more tender seedlings inside at night when the temperature dips below freezing.
How to build a cold frame
Let’s take a look at five examples of cold frame construction that are suitable for a variety of uses:
*PVC cold frame
PVC works great for cold frames because it’s lightweight, portable, and durable. Moreover, a frame constructed out of PVC piping and covered with a strong sheet of plastic is light enough to be moved from one part of the garden to the other. Here’s how to build one.
*This Old House cold frame
This cold frame uses a recycled window for the top and is placed on a foundation of bricks to make it more permanent.
*The Instructable Plan
This cold frame design also incorporates the use of recycled windows. It’s also a bit deeper than other cold frame designs and is handy for growing taller plants. Make sure the old windows are in the best shape possible (you may need to re-caulk them) before using them.
*The vegetable gardener design
This design focuses on a lightweight top – made of a lightweight sheet of vinyl that’s stapled to the edge of a lumber frame - for ease of opening up on warm days. The vinyl will deteriorate over time and must be replaced every few years, but it’s not a difficult job.
*They DIY Network cold frame design
Looking for insulation? This design has you covered with insulated sides that help with heat retention. Again, make sure your cold frame has proper ventilation so that you don’t overheat young plants.