Cold Frames

We have begun seeding inside (even though it is technically too early, Terry can't resist getting started!) and are making plans to seed outside. This year Terry is building cold frames which I am really excited about. These simple structures will allow us to start seeding earlier outside and also have greens through the winter. Here's how they work.

First seed trays planted and under the grow lights

Cold frames are built to create environments that minimize sudden changes in the environment. Throughout the seasons, the weather patterns are so irregular that it is the shock of thaw and frost cycles that affect the plants, not necessarily the cold. They are simple and cheap to build and a frame consists of a box with a glass top and no bottom that sits on the soil.  Traditionally they are built to be 12" high in the back, and 8" in the front, about 4' - 6' front to back, and should be south facing. 

 

We were given these old windows and they are perfect to use as our glass!

Inside the cold frames, the temperatures can be as much as 20 degrees warmer than the outside temperature. This is great for the winter, but in the spring you have to be careful and be sure to open up the lid to vent it to prevent crops from getting too warm.  

So what can you grow in them? Cold frames are not suitable for all plants and you still need to be conscious of what you are putting in them because things like tomatoes will not stand a chance. Good cold weather crops are carrots, swiss chard, spinach, arugula, and other hardy greens.  Terry has built 2 cold frames and we will be planting beets, carrots, cilantro, lettuce, radishes, spinach, and salad mix.  We will add 'Sweet Peet' to the soil where the cold frames sit to add extra nutrients to the soil.

 We are looking forward to using these cold frames and extending our growing season!