Depends on how cold. If it's just a bit below 60, you should be ok. You could pull them up closer to a house for extra protection, or if it's easy enough move it in and out. I do both in spring to get a jump on growing season here. We have a brick town home with an enclosed back yard and many nights they just stay right next to the brick. If it's repeated nights, or 50 or below, your basil will stagnate and quit growing. Keep in mind that basil is annual, so you can extend it for a while, but there's a point to just start new, from seed or cuttings. I say this having harvested all mine today due to expected frost tonight, so your 60 in Dec is sounding nice!

My basil grew and grew and grew, but the later cuttings weren't as good as the early ones, and now the plants are looking bad. I will sow this repeatedly next year. So I agree, don't expect to keep the same plants alive for that long. They are a short-lived annual.

Ok thanks a lot for your feedback.

So you're saying that even under the best circumstances, with consistent temperatures and lighting, you wouldn't be able to keep basil growing for more than a year?

I realize they're annuals, but does it really know how long a growing season is, if the environment never changes?

I am sure the plant "knows" that it is aging, and wear with age it will, like any other vegetative growth.

Just plant fresh basil, it grows readily from seed... I don't think there is a good reason to try and keep an aging plant alive indoors IMHO, unless only briefly, the good leaves will wear out and any new ones won't grow well. You can freeze blanched or pureed basil, too.

Thanks for the info. I agree it's good to refresh the basil periodically - I was more just wondering for my own benefit.

I've been drying the excess basil I've grown throughout this last season and it's worked pretty well.

I suggest making pesto if you have a blender.

The fear for most plants in the winter is the frost and freezing. If you don't get that low, then many of your plants can remain outdoors. (Eg I have read about some people who grew their orchids outdoors all year long, just like in the tropical areas where these orchids might be found. Their region was not tropical but it just didn't freeze often)

I'd say to let the basil keep growing and see how it does. You can get new ones in the spring but if your old one keeps going, it should be a fun story to tell also.

Thanks very much. I live in northern NJ, so it's already too cold to expect any further growth outside.

To make it worse, the way my house is situated, the plants don't even get much light during the summer :-)

They still did quite well this past summer. Looking forward to starting inside again.