Hi, Dave,
Probably not the best idea to add anything to the pot - you don't want your fig to compete with anything else for nutrients and water. It needs all you can give it to grow and produce the healthy fruit you want - especially since it will be grown in a pot. Also, whilst it is possible to grow a fig in a container, 'Brown Turkey' will get large. Over time, it will need root pruning to keep it happily growing in a container.
Kathy C
Replied: Monday 27th of February 2012 09:45 PM