mikevan

In the winter I water much less - let the soil dry out a little bit. So long as it's slightly moist a knuckle or two below the surface, the nanner won't desicate too much and you can monitor it too. You want it just above wilt level. As to coolness, I'd opt for 50's during the day - survival is more important than growing if you've uncertainties. In the 50's it will largely be dormant, tho with consecutive warm days you may still get a leaf a month or so. The humidity will be the saving grace tho - on cold nights. My unidentified nanner survived tempuratures down to 20F when the heater went out, namely because there was no desicating air movement and because the humidity was so high. A layer of ice even formed on the glazing and containers froze over - small cups of water froze solid but the nanner only suffered defoliation, which it replaced when it warmed back up.

Concentrate to keep it above freezing rather than to maintain an ambient tempurature. My heaters were aimed in a way that created a warming bubble around my tropicals where the rest of the greenhouse got chilly. Trying to create an ambient tempurature in there will be prohibitively expensive - glazing is a terrible insulator - an R-factor of .8 to a little less than 2 depending on the material and layers. I kept chocolate trees, coffee trees, taro, lemongrass, ice-cream bean trees, cashew trees, vanilla orchids, etc alive this way with only a single layer of poly and nights getting down into the upper to mid teens and didn't kill myself with heating bills. My new pit greenhouse will hopefully be even more efficient in tempurature moderation...

Don't neglect ventilation on clear days tho - even if it's cold outside, a little bit of sun can cause temperatures to skyrocket inside to over 100F very quickly! Only on the coldest days did I maintain temps below 100F without ventilation - and with ventilation the average high was in the 90's regardless of how cold it was outside! If you can stick a large bucket or barrel of water in there with the nanner tree, it will help moderate the temperature - absorbing warmth during the day and releasing it over the night.

In any case - I have zero fungal problems in my greenhouse. I don't over-water - keeping things a bit on the dry side, so that no doubt helped. I also kept the air around the plants moving at least some of the day - either with ventilation during the day, or the heater at night. But fungus can happen - keep an eye out for pockets that remain cool and dark and still and moist.

Have fun,
Mike