Sunlight is generally considered a plentiful resource; the exceptions highlight the importance of solar energy to agriculture. Agriculture and horticulture seek to optimize the capture of solar energy in order to optimize the productivity of plants. Greenhouses convert solar light to heat, enabling year-round production and the growth of specialty crops and other plants not naturally suited to the local climate. Various strategies are commonly used to extend the spring and fall growing seasons by a few weeks. An energy-efficient solar-heated greenhouse can provide an inexpensive and successful tool to fill the gap for farmers with winter garden-envy. A variety of cold-hardy species, including vegetables, salad crops, restaurant garnishes, and fresh cut flowers can be successfully and economically cultivated in a properly designed solar-heated winter greenhouse with little or no added heat. Of course, one could preserve summer crops by canning and drying, but fresh vegetables in winter months would make a healthy diet more likely. This study discusses basic principles of solar greenhouse design, as well as different construction material options.