Now, in the midst of summer's warm temperatures, may not seem like the time to be thinking about the cold weather that will be returning in fall and winter. But if you'd like to continue enjoying the bounty from your home garden as the days shorten and cool and frost threatens, now is the time to start planning a seed sowing schedule for fall-harvested crops. And it's also a great time to build structures like cold frames and raised bed cloches that offer protection to plants and can prolong your harvest later in the season. The extra protection these structures afford can extend your growing season by a month or more depending on your climate, especially if you plant cold-tolerant crops like greens, cole crops, and root crops.
Cold frames are boxes with a clear hinged or removable tops for access and venting that are easy and inexpensive to build at home using some simple tools. Make the back or north panel of the box a little higher than the front or south panel to maximize sunlight; side panels in the 12-15 inch high range work well. A clear fiberglass panel for the top lets in light and provides some nighttime insulation.
A raised bed cloche is another easy to build season extender made by stretching plastic sheeting over PVC hoops above a wooden frame. Such a cloche allows you to protect taller plants than can fit in a cold frame. Oregon State University Extension offers plans online for building this handy season extender at OSU Extension Service. For a handy fall-harvest planting calculator that lets you figure out when to plant for a fall harvest based on your fall frost date go to Johnny's Selected Seeds.(Image by Sam Angima, courtesy of OSU Extension Service)