Fig plants are sensitive to cold, and many gardeners living in colder climates opt to grow their plants in pots so that they can be moved inside once the temperature drops. However, with some additional care and protection, a mature and dormant fig plant can survive winter temperatures as low as 10 degrees F.
Reduce the amount of water you give your outdoor fig plant. Begin in the fall and gradually cut back on the frequency and amount of water that you give the plant. In allowing the soil to dry out, you encourage the fig plant to enter the dormant phase, which makes plants more winter-hardy.
Spread a thick layer of straw mulch at the base of the tree. This will help insulate the base of the tree and keep the crown alive.
Insulate the fig plant. Erect a simple frame over the plant and cover it with polyester frost blankets that are anchored to the ground with stones, cinder blocks or other heavy objects.
A more extreme but effective option is to dig a hole next to the plant, tip it over and bury it.
For a more decorative option suitable for less extreme winter temperatures, warm the plants by hanging string lights from the branches and placing landscaping lights at its base. If kept on all night when temperatures dip to their lowest, the lights will sufficiently warm your fig plant.
Do not water your fig plant during winter. The roots should be kept as dry as possible. Remove any snow that collects at its base so that the water does not seep through to the roots as the snow thaws.
Check on your plant periodically. If any limbs have frozen, wait until spring before pruning them.