Gardening with a cold frame

When there was three feet of snow on the ground in the Denver area in early January, it was hard to imagine vegetable gardening was just a few months away. But here it is the end of March, the snow is melted, the soil workable and the days are warm and sunny. At least for now – March and April are Denver’s snowiest months!

This early season warm weather has me thinking of planting my first crop of “cool-weather” vegetables. By that I mean, veggies that don’t mind cool, even colder weather – things like lettuce, spinach, radishes and onions. Many varieties of these vegetables are quite hardy and don’t even mind a little snow. In fact, a crop of spinach and about a dozen green onions remaining from last year’s fall planting survived the winter – even with three feet of snow piled on them for a month.

A few years ago, I decided to try planting early by using a cold frame. I thought of it as a way to extend the growing season. A cold frame basically is a mini-greenhouse. It helps warm the soil so seeds can germinate faster than if they were planted directly in the soil with no protection. Some gardeners use a cold frame to “gently” expose seedlings that were planted indoors to outdoor conditions. My cold frame allows me to extend the growing (and eating) season a good four- to six-weeks. I use an old glass storm door and some 2 X 6’s. The Victory Garden website, a long-running gardening show on PBS, has a good explanation of cold frames.

Well enough about cold frames. I already have turned the soil where I’ll plant my early season crops. Now all I need do is add compost to the soil, select what crops to plant and set up my cold frame. I’ll probably get started the end of March. If all goes well, I will be harvesting my organic radishes and green onions for salads by late April, and picking lettuce and spinach in early May. Until then, I still will be enjoying the spinach and onions in my garden left over from last fall.

Doug Magee