I'll let others that grow their fig trees in containers give you their specific recommendations. I grow all of my figs in the ground in South Louisiana and have similar concerns to yours. Unfortunately, I do not have the option to move them to a shelter whenever the outside temperature dips in the Spring.

This is FYI only and for those other forum members who might want to know some "WHY's" behind potential leaf damage............it is not just about AIR TEMPERATURE. It is also about wind, leaf temperature, and air humidity level. On a windy night with clear or cloudy skies LEAF temperature will be nearly the same as AIR temperature. However, on a cold, clear night with little to no air movement.....leaf temperature can easily drop 3 to 4 degrees lower than the ambient air temperature. (It can drop as much as 8 degrees in my area.) This is because of the radiation heat loss of the fig leaves. The rate of heat loss of those leaves is a function of the air's humidity level. At higher humidity levels often frost will form on those leaves. So, while the ambient AIR temperature might only be 35 degrees F......the actual LEAF temperature might well be 31 to 32 degrees F. That temperature could affect tender new growth.

In my area it is not uncommon for us to see frost form whenever the ambient air temperature is at 40 degrees F or below. This means that the actual leaf temperature reached 32 degrees F or below which froze the dew that condensed on the leaves as the dew point of the humid air was reached during the night. Late Spring frosts can kill fig trees in South Louisiana......especially if the outside air temperature has been cycling through several periods of warmth and cold. Yes, in my area, damaging frosts can form on fig leaves with ambient temperature as high as 40 degrees!! Ask me how I know and what I fear most at this time of year. It is really about leaf temperature and that is a bit harder to measure.

Dan

Hi Keepitlow,
what i have done thru out the years is bring mine out onto driveway (blacktop) that gets nice and warm when temps are in high 40s at least to somewhat get a jump start on the season in my area.The nights they come in when temperatures will get below 40, the real young ones come in regardless unless temperatures are 45 or so above. Recently i left my mature trees out when temps hit 37 but thats rare for me to do as i feel im defeating my purpose and they should have been in the garage.
Martin

keepitlow,

For what it's worth.......I consider "diesler" and "herman2" to be our EXPERTS on growing fig trees in containers in their cold climates. You will find their posts to be informative and helpful.

Dan

I have several fig trees growing in containers and I bring them in whenever the temperature is forecast to drop below 40 degrees. In the past I was less careful and had a tree that was already leafed out pretty good lose all of it's foliage when the night time temperature unexpectedly dropped to about 30 degrees. Weather forecasts are never totally accurate, so just to play it safe I use a forecast of 40 degrees as my cut off.

Joe

Thanks Dan for explaining the phenomenon. Good refresher.
I guess that heat radiation may explain one phenomenon I observed during the extreme low temperatures of January and February. I kept my new plants in front of a west facing window where outside window pane may be facing -20C (-4F) or lower temps at night. I noticed that the new emerging leaves will look dissicated and die whereas the matures leaves will have no problem. Then I moved the plants far away from the window and the problem disappeared. A week ago I brought the plants back in front of the window and because of the absence of very low temperattures the emerging leaves survive and do not show any sign of dissication.

Thanks. If no leaves but just green tips unflolding is the advice the same?

Even in humid areas, frost simply CANNOT form on leaves when the ambient air temperature is greater than 40 degrees....unless of some freakish, unusually high atmospheric pressure condition. Yes, atmospheric pressure affects these variable too. It is interesting that 40 degrees F turns out to be the air temperature where both Northern and Southern fignuts become concerned for their precious trees. I didn't realize that until this discussion......

Dan

Keepitlow ,
it it helps give you idea's mine never have leaves when i start doing this and they still do not have leaves now and some buds are green not too many and many still tan brownish. The wind that hits my plants on driveway are North winds at night and i somewhat hide my small plants next to the larger pots all plants close up to the garage door if they stay out at night, there protected on the other 3 sides for the most part by garage door, car and boat. I do this until im darn sure the night temps will stay steadily above 40 or so then they go in yard for season, now there have been a few times over the years where i have had to bring em back in garage oh what a pain cause i dont have a rear garage door or that would be so much easier cause its a bumpy ride over the type of cobblestone walkway and the side grass that i have to wheel them thru.
This is what i do always been doing but its not as bad anymore now i been retired and can enjoy them so much more, i wont go thru this 1 day when we move out of this lousy weather.
Ok too long of a post, just i tried to explain what i do with my plants before they get to the backyard.
Its not that bad and when im too old i wont actually have to do none of this. ; )
Martin

ottawan,

The phenomenon that I described applies indoors, outdoors, or in green houses for that matter. Yes, the radiant heat loss of the leaves on your tree near your cold window could have dropped the leaf temperature too low.....causing the leaf damage that you observed.

Dan