Figs are warm weather trees, and are best suited to the mild winters in growing zones 7 through 11. However, if given adequate winter care, fig trees may be grown in zones as cold as 4. But gardeners in these areas must take extra care to provide adequate frost protection. If exposed to freezing temperatures, a fig tree will not fruit or flower the following year, and it may even die. If the forecast suggests a chance of frost, you must protect your fig early if you intend to enjoy its fruit next year.
Do not water or feed your fig tree a few weeks before you expect the first frost. This will encourage the tree to go into its dormant stage.
Prune your fig tree back by one-third.
Spread a 4-inch layer of organic mulch around the base of the tree.
Erect a frame over the plant by placing four poles in the ground around the fig tree. The poles should be a few inches taller than the fig itself, and placed around the tree so that they are just touching the outer-most branches.
Wrap foam insulation around the poles, making sure not to forget to cover the top of the frame. Secure the insulation with duct tape.
Cover the foam insulation wrap with a heavy blanket. It can be secured by rocks placed on the edges of the blanket, or with string.
Wrap the blanket with a plastic sheet to protect the tree from moisture. Secure the plastic sheet with duct tape.
Leave the structure up until spring, when all threat of frost has passed.