Hi,
my expierence with black mission.
Some dieback stored in attached garage near Chicago,was lightly watered in the winters to keep roots from drying out
sometimes with snow.

Was limb pruned and root pruned to match pot size of 20g and was fast grower , needed to be kept in check.
Produced good amount of figs but eventually discarded for
taste .
Martin

A 6" pot is awfully small....

I personally would slip that small tree into a 5-gallon bucket, making sure it has drainage holes, and then store the tree in your garage when temps. start to plunge. The extra mass of media around the roots will insulate, and will be slower to react to temperature extremes, than just a few ounces of soil in a 6" pot. Make sure you keep the tree hydrated while dormant.

If you don't want to disturb the roots now, slip the tree in the 6" pot, into the 5-gallon bucket, and proceed as above. Of course the bucket will contain growing media. Double-potting works. Then, you could up-pot your tree next spring, just before bud break.

"Black Mission" can do very well in a large container....the larger the better. I grow in 18-25 gallon containers, and avoid hernias by rolling the potted trees around on dollies. Alternatively, you could also plant the tree into the ground, eventually, as the tree becomes larger, but containerized trees will be your best bet while tree is still young....less than 5 years old. Older trees are somewhat hardier than young trees.

Standard pruning methods for figs will keep that "BM" within bounds, and manageable.

Post some photos of your "BM" figs next year. : ))

Good luck.

Frank

This post was edited by BronxFigs on Sat, Aug 30, 14 at 9:20

Sandy,
This may be already be posted and I see Frank has already given you great advise. So, to the department of Redundancy department.
None the less;
I live in Warrenton Va and have a Black Mission in a 5 or 7 gallon pot (off the top of my head??) that I put into my garage every winter. It will be OK in a 6 inch pot but will be in a more stable environment in a bigger pot. I use fafard #52 soil mix which I get from Griffins nursery supply in Richmond. It will need very little water - but you can not let it dry out completely. I usually water my 1 gallon size figs 2 times per month but my larger pots only once.
Figs are super easy and if you know anything at all about pruning you probably know enough to deal with fig trees. As some figs are grown for their breba crops more then their main crops pruning gains more importance as the brebas grow from the previous year's wood. You don't need to worry about that - until you start collecting figs. And you will.