I cannot answer all your questions, but have grown cherry tomatoes through the winter in my small, heated greenhouse. Not extremely plentiful without auxiliary lighting, but nicely-textured, sweet and with just the right amount of acidity, these were truly "garden candy" when I was puttering in the greenhouse. Without any auxiliary lighting, production falls to practically nothing, but then picks up again around late January or February and increases from there onward. The plants had the most amazing, gnarled, trunk-like stems. I discarded them when the young seedlings (from those same tomato plants) reached production size. The older ones seemed to be tiring, but I cannot say for sure whether that was because their time was near or because I probably had turned my attentions to the demands of the outdoor gardens.

With adequate lighting and fertilizer, I'm sure you could keep a tomato plant producing throughout the winter. Some varieties are probably better-suited for this type of culture better than others.

All this did make me wonder, too, "What makes an annual die when weather is optimal?" and whether a lot of these plants are, in fact, annuals or tender perennials.

Considering the constant production of flowers and fruits, I can see where the plant itself might become exhausted.

I'll be looking forward to further posts on this.

I had the understanding that tomatoes and peppers are perennial. I've grown a two-season cherry and a Sungold. At the end of year two, they were still going, but just tired and spindly and leaf disease was setting in. Can't say I blame 'em, come winter, I'm tired too!

I kept a Hungarian Yellow pepper going 4 full seasons. I can't say I nursed it, it was more like torture, as it spent most of its life in a too-small pot, which was always drying out causing the plant to drop most its leaves. The stem did indeed resemble a small brown tree trunk more than a green stem. It was still going, but so gnarly and sparse that we just let it fade away... But man, it made some spicy peppers in seasons three and four, boy howdy!

-Ed