Extend the Season with a Cold Frame
September 5, 2013
With September already here and the leaves starting to change it feels like summer came and went too quickly! Have you consider extending the growing season with a cold frame? They are a very useful thing for gardeners to have on hand as they can also help start seedlings earlier than the area permits. They can also help protect tender plants well into the fall and you can even force bulbs in them during the winter months, such as tulips, hyacinths, daffodils, and crocuses.
There are lots of options on the construction of cold frames — whether you salvage old window tops or use polycarbonate — the most important key is to consider the height to suit the needs of your plants. For durability I would suggest you use 1 x 8 cedar boards. There is also an array of kits (such as this one) out there if you do not have the required materials.
Once you have decided on your materials, you have to consider placement of your cold frame as there are certain factors that are critical to successful use. Make sure to place your cold frame in a well-drained area that will not get flooded. Also make sure to orient the frame so the window faces south, this will protect it from easterly and westerly winds and help capture good light levels. It’s always nice to have them situated near a water source to save yourself some work. Consider painting the inside of the frame white or silver to help reflect more light on to the plants but don’t treat the wood as you don’t want to poison your plants. You may even want to consider burying a heating cable to extend the season even more! Keep in mind that on really cold nights you will need to consider increasing the insulation around you cold frame with blankets, old carpet, straw, leaves, newspaper or even snow. This in mind also consider on the warmer days ventilation will be necessary.
Here is a list of veggies and herbs to prolong in the fall season.
Plant, Height, frost tender notes
Basil, 30-60cm, frost tender
Beets, 30cm, tolerates light frost
Carrots, 30cm, tolerate light frost
Broccoli, cauliflower, cabbage and Brussel sprouts, 30-75cm, tolerate light frost
Eggplant, 60cm, frost tender
Onion seedlings, 30cm, tolerate light frost
Peas, 90cm-2m, tolerate light frost
Peppers, 60cm, frost tender
Radishes, 30cm, tolerate light frost
Salad greens, 30cm, tolerate light frost
Tomatoes, 60cm to 2.5m, frost tender