I've been asking a lot of questions lately. But I have another about gnats. I've been reading about them on old threads. Those discussions always seem to deal with the the problem inside. I just noticed a good number around the base of one of my tree - in a container. Is that anything to worry about?

People have posted that they are not an issue outside (e.g they just blow away), but last year I found this was not the case for me.  They certainly weren't as bad outside as they were indoors, but they were still around.  They seem smart enough to deal with the wind -- i.e. on windy days, they just hunker down in the soil;  On calm days, they get out and about.
  Last year I dealt with them using BTi.  This year I discovered some in some (non-fig) plants, so I just stuck a yellow sticky trap near them to address the problem.  I think a combination of those things might work for you, too.
Jim

Tony, I use a three prong approach to dealing with them. I use the yellow sticky traps, BTI and Carnivorous Plants. Additionally, I
water only from the bottom as long as the plants are inside and anytime they get water they get BTI

The yellow sticky traps and  mosquito dunks work well for me