I've given up growing BASIL in winter! 

Thanks for the video and many tips! Not having much own experience yet, but watching loads of videos/reading a lot: - Cut the cuttings at the bottom just below a couple of leaves. - On the cuttings leave only 1 or 2 top couples of leaves in order to keep the photosynthesis going, but reduce the need for supplying water as there are no roots yet. - Put the glass with the cuttings into a pot or similar in order to darken down. The roots are growing earlier and faster that way. - Split the plants from the super market immediately, don't wait 3 or 4 days. The small (not damaged) ones, which you skipped, might have been the better choice to plant again. - Don't reuse the compost from the original pot from the super market, there are not many - if any - nutrients left. - They need a few hours of sunlight (or maybe a grow light as it has been mentioned?). - Try to avoid the dry air from the radiator. If not possible, mist them every day. Hope that helps a bit.

It could be a lack of sun but I would check the Ph of that compost. Normally it isn’t an issue but you couldn’t rule it out either.

Have you tried grow lights? It will help tremendously. You can buy LED grow lights.

Grow lights would likely fix the issue

I grow African Blue basil cuttings indoors over winter to plant out in summer for the bees as it flowers for months. Some of my cuttings fail as yours have, but enough survive. I mist them with water from a hand spray bottle every few days, and now and again I mix a solution of epsom salt in water and turn the pots upside down and submerge the stems & leaves for a few secs. If you're using peat free compost then that is often poor quality for growing in, try mixing some garden compost in with it.

basil leaves dried become bitter, taste very bad. Dried spikes have good taste

damn, now I'm hungry :D Not enough sunlight? I grow mine from seeds, doesn't alway take tho. Even in summer, but you sow so many that you always have something

I love basil....... Brush! 🤣🤣🤣 BOOM BOOM!

We're down in Lancashire and all the basil plants in the supermarkets down here look pretty much like that one you bought, so I wonder if it's a supplier issue?

Might to dry air.

We have an indoor basil that's at least eighteen months old at this point. Might be two years. It's clearly well past its prime, but it's a fun game of "how long can we keep this thing alive". He's more of a pet than a herb these days! Edit: First photo I can find is from August 2021, and was at least a few months old then. Might be a 2.5 year basil!