Basil is an annual, not a perennial. So indoors or out, it's not going to last forever. My outdoor basil started flowering recently, and though these are easy enough to pinch off to slow undersirable characteristics, it signals the beginning of the end. If your basil is doing bad inside, it may be time to harvest, dry the leaves, and store, before it gets any worse. Basil is a plant with tropical roots (southeast Asia), so keeping it indoors, in low light with low humidity, it will not thrive.

Thanks Butchie. So when you say Basil is an annual, do you mean only in our environment....or is it also an annual in SE Asia?

I'm just trying to understand what 'annual' means for plants that could be kept indoors. I thought the term 'annual' only applied for outdoor plants that are able to sense the end of the warm season, and that naturally die in the Winter? If a basil was grown indoors, how does it know it's time to die? Is it simply due to the shortened hours of daylight?

I know I've seen basil plants available year-round in the stores so....if someone were to buy one say in December, would it last until the next December or so?

I guess I'm trying to understand what signals the plant is getting, that it's no longer thriving, if the conditions in which it's been living are unchanged (unless as I mentioned, it's simply the fact that the daylight hours are shorter)? And if that's the case, would a sunlamp make a difference?

Tx.

That is a good question about the annual/perennial thing. It is generally treated as an annual but since it starts to go woody at the base I would suspect that in a year round hot sunny climate it would last more than a year. It originally hails from places nearer the equator and so would be adapted to a similar amount of light year round. I can never get it to last through the winter because I do not have enough light indoors. I can only suggest you experiment. To get a fresh basil taste through the winter you can sow basil seeds regularly and use them as cut and come again seedlings. It looks like a garnish at that size but still gives you the real basil flavour. Personally, I just do without basil in winter and enjoy it all the more in season.

Wow, a foolproof way to grow fresh basil in winter would be sooo welcome at my house! I love the fresh taste and don't think dried or even frozen in ice cubes is the same. I save seeds from year to year and it's easy to grow, but never seems to like being in the house unfortunately!

Probably the best chance of a healthy indoor plant would be with good air Circulation, good lighting and setting on wet gravel. But that may not help for very long with all the dry heated areas in the home. I was watching a TV show with a 13 year-old Chef. He put 5 cups of fresh basil leaves in his sauce, so I tried much more than I usually use and my sauce is quite dark but we sure do enjoy the flavor so expect I will continue to use more basil than I use to use. I just may end up putting more into my flowerbed in order to have more. Here if we want fresh herbs from the store they can run up to $5 for a small amount in a special container so it pays for all who want fresh herbs to grow them for themselves.