Pam, I don't have experience growing vegetables indoors over the winter, but I think sunlight will more than likely be a big issue. Even with a southern exposure, the short days of winter will not provide enough light to bring a plant to the flowering and fruiting stage.

I suggest you talk to the folks at the Growing Under Lights forum, linked below.

Good luck.

Susan

Here is a link that might be useful: Growing Under Lights

I agree with Susan that you will need artificial light to grow things indoors. I satisfy my need to garden in the winter by winter sowing. I don't have room indoors for lights so I put the containers outside. You can check out the Winter Sowing forum for all the info you need.
Joann

Here is a link that might be useful: Winter Sowing forum

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.