I've been getting a lot of question regarding winterizing fig trees. Specifically, is it too late to plant them now that it's the fall season and should I buy young fig trees if we're so close to winter?
The way I see it, you have 3 options:
Plant your tree in ground. I recommend planting your fig trees in ground (even in short season climates like mine) vs. continually growing them in containers. Planting your tree in the fall is what I believe to be the best option for your tree and actually the best time of the year to plant it. However if you're in an area that drops below 15-20F in the winter, your young planted fig tree might take some winter damage. Depending on how weak and lignified your tree is, that could be a very bad thing. So if you're going to plant your fig tree in the fall in a cold climate, which I wholeheartedly recommend and have done many times, you must protect that tree in some way throughout the winter and early spring. Either by wrapping, covering, ringing with woodchips or by just simply planting a few bottom nodes below the soil level. Another great winterizing tip is to cover the soil with a woodchip layer to insulate the roots. The benefits of planting your fig tree in the fall is many. The biggest is actually getting a much more vigorous and prolific start to the following season as even at soil temperatures of 50F, your fig tree will grow roots. It probably won't grow top growth, but it'll be getting itself more established than you would think.
Bring your tree inside for the winter. This is the rookie mistake many people make. I see it every year from new fig growers and it always disheartens me to see them discouraged by failure. Without heavy duty supplemental lighting, spending 6 months indoors will likely set your tree back rather than getting it off to an early start to the season. A sunny window really is not enough. What you need is warm soil temperatures and additional lighting. Usually you'll need a much warmer indoor environment than what we run our indoor thermostats at during the winter season. Ideally you can keep the soil temperatures above 70F. Otherwise it'll be like a houseplant, but a very root rot prone houseplant that is easily overwatered and could very well die. Something else people constantly overlook is pest pressure. Spider mites and scale can become serious issues indoors if you don't have a trained eye. Out of control, those pests can also seriously set back your tree and even kill it.
Let your potted tree go dormant. This is the safest and easiest option of the 3. Assuming that your tree has lignifed somewhat (not necessarily is totally brown, but has mostly hardened growth), simply allow your small potted tree to get hit with 1-2 light frosts. This will like the rest of your potted fig trees send the tree into dormancy. From there.. it's as simple as putting it away in a place that stays between 20-50F until spring. A root cellar, garage, insulated outdoor structure or a very cold basement will do and I stress the word very. The basement is probably the last place you want to winterize your trees. Having said all this, what you want to avoid is a hard frost. My very well lignified fig trees that you see in the photo below can withstand 20F and have in prior seasons. Just because they're young, doesn't mean they're more cold sensitive. The real key here is the level of lignification of your tree. So if your tree is not well lignified, maybe all it can handle is a light frost. Alternatively.. if you're very concerned about lignification. Put the tree in a sunny window indoors for about 4-6 weeks. This will give the tree enough time to lignify indoors, so that you can put it outside safely and allow it to get hit by a couple frosts. Lastly, by allowing your tree to go dormant, you are doing your tree a great service. There are huge biological benefits when allowing the dormancy process to occur. If I were to keep my tree indoors all wintertime, not only may your tree be suffering come spring, but you are also missing out on the benefits the dormancy period provides, which by my estimation are huge.