Growing plants in a greenhouse environment is like growing any other container crops. There must be adequate light, irrigation systems and proper media selection, but greenhouse production has its own unique set of considerations and factors. Heating, cooling and good ventilation are the main concerns of a greenhouse system. During the short winter days and much of the fall and spring as well, Oregon has its share of cloudy days. The clouds diffuse much of the light needed for good crop development. Supplemental lighting systems are needed to extend the growing period. To maintain proper temperatures for crops, heating and ventilation systems are vital components for a greenhouse production operation. There are many greenhouse companies that can assist you in setting up a functional greenhouse for your specific needs. They can advise on irrigation systems, timing clocks, types of structures, benches, heating and cooling systems and most everything you need to get growing.
If you don't heat and light the greenhouse all winter you can still grow cold hardy plants like kale, lettuce, spinach, Brussels sprouts, radishes, carrots, turnips and leeks through the winter and into spring. Greenhouses also allow you to start planting 6 to 10 weeks early. A greenhouse can be kept frost free if temperatures do not go below 39 degrees. This is fine for many plants that simply require frost-free conditions over winter – especially if they are only watered sparingly (if at all).