Where do you live? USDA zone - state - large city near you?

Al

When conditions are favorable, root growth will occur... even during dormancy. The problem is many times the conditions that keep the tree dormant, also prevent the roots from growing.

In Houston, I start root work once the leaves drop (i'm not sure they ever fully go dormant here). During the cooler winter months while the top isn't doing much, the roots are reestablishing themselves in the container (this is the primary benefit of re-potting early). The correlation between timing of re-potting and timing of breaking dormancy is not so clear. What I have found is that most of the trees seem to break dormancy within a three week period of each other, regardless of when they had root work done. There might be a slight edge to the earlier one, but its hard to tell. Any advantage is not noticeable.

For the trees I have in NJ, I wouldn't do root-work in the fall. Since there is minimal water being applied to the container while the tree is dormant, the growing mix is much drier and the trees need to keep a better foothold.

~james

I live USDA Zone 5b,
figs will be overwintered in a cold room (Cellar room)
where temperature is going to be somwhere from 2*C to 8*C

Nude_gardener is that 2 to 8 above zero? Im asking cause that seems to cold to me but not sure. My garage probabley gets no colder than 15 or 20 when we have a real good cold spell. What i do is root prune them in late winter and before they would start to bud, i have once root pruned after they budded and just leafed out with no bad effects but that might not be a good idea, its just that its so cold in winter. I never root pruned after tree's just went dormant so im not sure what that would do to tree.

Hi dieseler
These are 2 degree centigrade to 8 degree Centrigrade, the real simple scale where freezing is at ZERO degree C and boiling is a plain 100C ! No clutter of numbers.

nude gardener: Is your cold storage insulated from the rest of the house. I live in Zone 5A but my cold storage in the basement stays above 5C (5C to 8C) which is Ok for dormant plants but I would prefer your 2C~8C (better 2C to 7C). My cold store has its top, north and west sides open to outside. I was thinking of using the silver coloured buble insulation on the side attached to the house. I have real concrete walls in the basement.

I have read that root growth occurs above 55F (12.8C), Al has stated root growth occurs above 40f(4.4C). It seems at best, your cold storage area is borderline for root growth.