I think that your basil would benefit with more light. Perhaps you could move the plants closer to the light source and/or increase the light intensity.

Basil is an annual and grows for one growing season. I've heard of people taking cuttings and starting those to stretch out its life. I always plant new seed come spring so perhaps others that try to keep it going can other advice. FataMorgana

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.

I grow basil indoors and have some fresh basil available year round for cooking. It's not the easiest to grow indoors, especially in the winter. For growing media/"potting mix", you can refer to the link(s) above and mix your own container mix. I've also had reasonably good luck for herbs (rosemary, sage, basil, cilantro and parsley) in either "Bonsai mix" or "Cactus, Palm and Citrus" mix. Sometimes, if the mix seems to retain too much water, I'll add some perlite to the mix to enhance drainage. I use clay (terracotta) pots with saucers. I don't put anything in the bottom of the pots for drainage. I actually use a single paper coffee filter to keep the mix from falling out the drainage hole. I fill the saucer with marbles (or stones) to keep the pot from sitting in any water that drains from the pot at watering time. The water won't wick up the marbles or stones and back into the pot, it will just sit and evaporate from the saucer. Temperature needs to be warm. My hanging planters are in the kitchen, not far from the wood stove which is supplemental (often primary) heating for the kitchen and bedroom "apartment" part of our home. Heat usually isn't an issue. It's 75F or warmer most of the time, with occasional nightly dips to the mid 60's. Light is also critical. In my kitchen, lighting generally is extremely bright. I've got a 4 tube fixture with T8 bulbs in it for general lighting. I mix 2 "Warm white" (2700K), 1 "cool white" (4100K) and 1 "daylight" (6500K). The kitchen was bright enough with just a two tube fixture, so it's very bright, even a bit harsh with that lighting. But that's not enough for "full sun" plants. It's not even close. Beyond that, there's a light fixture with an LED "spot" light built into my hanging planter. Those lights are fairly intense and look quite harsh. For basil and other leafy herbs, use an LED "aquarium" bulb with blue (~460nm) and white (15000K) LED's. Most "blurple" LED grow lights are heavy on the red end of the spectrum to promote blooming. That's probably desirable for "medicinal flowers," but that's not really what you want for culinary herbs. If I hang my planter/light setup in a sunny window with the light off, and put my hand where the shadow is in the pot, when I turn on the light, the shadow basically disappears completely. That's how bright your lighting needs to be for basil (or other "full sun" herbs) to thrive. Look for a bulb with a 30° beam angle (or tighter), and place it where the bright part of the beam fills the pot, but very little light goes beyond the edge of the pot. Usually, that position is a bit less than twice the diameter of the pot above the surface of the potting mix. Yellowing and dropping leaves indicates either too much water or insufficient light (or both).