A lot of people ask me how often to water domant potted fig trees during the winter. Here is what I say in my book Grow Figs Where You Think You Can't:
Watering Dormant Fig Plants
Dormant figs are more likely to die from overwatering than from underwatering.
While plants are dormant, it’s important to strike the right balance in watering: enough that the dormant trees don’t dry out and die, yet not too much that the roots rot. I usually check them about once a month.
If you’re not sure whether your plant should be watered, stick your finger in the soil and feel around, digging down a couple of inches to feel if it’s moist.
In winter, you want to keep your plant dormant, which requires cool, dark conditions.
COOL + DARK = DORMANT