Posted: 16/01/2017 at 18:46
Hi Max - you're welcome.
Bear in mind that Basil originates from Thailand - not the Med. So we're trying as best we can to imitate the tropical environment that it comes from, and mid-winter in the UK is going to be a struggle for it.
The plant would like very warm, humid conditions with about 12 hours of strong light every day - and it's not going to get that here at the moment.
Indoor basil will lasts as long as it looks edible - a few months realistically if you're lucky. Sow just a few seeds every month from summer and you'll be good for a winter/spring supply. Once they have a few sets of leaves, pinch the top out to get a bushy plant.
All plants are driven by light, only light allows them to use the feed we give them. With little decent light this time of year just an extremely dilute feed now and then and let the compost almost dry out before watering again. Use a fertiliser not designed for flowers as it's leaves you're after.
Fusarium wilt is quite possible. Your plant doesn't look in the best of health for the reasons above leaving it weak and open to infection.
I sow basil in a propagator in March and get masses of the stuff by mid-summer. I don't bother after that as I've usually ended-up with plants that look rather like yours :)
Best of luck