I would build a cold frame, with a sloped drainage pan so the water drains off your deck. I would also buy a couple of heater cables and bury them in the soil. I would also put some type of insulation around the coldframe. This should keep the soil warm, and the inside temp of the cold frame well above freezing. You will have to watch very closely for disease. Mother nature isn't easily fooled.

Hi, I bought two juwel 1000 cold frames many years ago from a.m. leonard and have had great success with them. This link is for a larger one... http://www.amazon.com/Juwel-Oversized-Cold-Frame-1500/dp/B001FA9XJI They are a little fussy to assemble, but have been great. Yes, you will need an opener. A few posts down I wrote my experience growing through the winter. http://forums2.gardenweb.com/forums/load/strucs/msg0901065728313.html?2 Good luck

I have grown spinach outdoors without a cold frame and it stayed green and edible all winter. As soon as the weather warmed a little, it began to actively grow again (I recall this happened in March). So, spinach is one crop you should definitely consider. However, I wouldn't say that my spinach actually grew in the winter, it merely stayed green, so plant it within the next month or so to give it a chance to grow to eating size by fall, then simply pick it all winter. The leaves became increasingly beat up as the winter progressed, so that by spring the old leaves were tatters. I think you could extend the growing season far into the fall with an unheated greenhouse. All of us will have tomato plants full of green tomatoes in the fall when the frost kills our plants. with a greenhouse, I think you could keep your tomatoes and pepper plants alive probably well into December, enabling them to ripen the fruit they set during summer. As with the spinach, I wouldn't expect a lot of new growth or any new fruit to set late in the fall, but the greenhouse might extend harvest into December. Similarly, cold frames should allow you to grow veggies later in fall and earlier in spring than normal, but I doubt you'll actually have year-round gardening outdoors without a full-blown greenhouse. Even with a greenhouse, the short days make many vegetables hard to grow in winter. I think indoor vegetables will not actually set fruit, but you might get a few leaves to grow on spinach, kale, etc. I think I would not expect indoor vegetables to work, but you can try and see what happens. You might do better with a couple of indoor citrus trees which, if you have plenty of light, will flower and set fruit in the winter. A couple of potted plants won't be the same as an outdoor vegetable garden, but it is better than nothing. Besides, I think once you get the hang of it, cold frames can extend outdoor gardening for about 10 months in PA, so you won't be out of action for long.

Yes, ideally the soil in a cold frame will be warm enough to keep the seedlings cozy if the temp should drop to freezing. Some people have additional elaborate insulation below the soil line to further concentrate the heat. But if your cold frame is on your deck, it should be easy enough to throw some blankets or quilts over it if the temperature is marginal, or even move the seedlings back inside for the night if you're afraid of a hard freeze. You could also put in some plastic jugs of really hot water to bring up the heat before you cover up. But don't forget to open the top and provide ventilation for sunny days, the temps can rise quickly in an enclosed area. You might want to put a thermometer in and check it a few times a day to see what temperature extremes you'll need to regulate.