You can all thank Jeren who wrote me today asking about his Rainforest tree and whether it should come indoors now, because the answer is "Yes!"
It's time to bring your trees inside.
I've forgotten to bring plants in on-time before and paid the price. Not just with a mini jade that basically turned into mush before my eyes when hit with a sudden (although light) frost. I've seen my beloved cymbidium orchids covered in snow and that was not a pretty sight.
On the other hand this pine covered in snow it a lovely site- but this is not a tropical!
We think of the danger from frost, but please note that most of the "indoor" bonsai are tropical and/or semi tropical trees. That means that while frost will kill them, they can also be damaged at warmer temperatures than that.
Many trees will drop leaves at temperatures under 10C or even 15C. (50-60F) and because they have dropped these leaves as a stress response, it makes the follow up care trickier, since the trees will be in a more delicate state.
I hope that makes sense. It's as if they have been shocked and it has weakened their immune system. On top of that, it's easy to think that you have killed a tree that has just dropped all its leaves and many trees have been tossed when in fact they could have recovered.
In a perfect world the best way to bring your trees indoors is gradually, but that might not be possible now- however, you can:
1. Move trees into full shade during the day, to help them get used to lowever light levels in the house
2. Bring them indoors at night and outside for the day as long as the days (in the shade) are still above 60.
3. Check your trees for bugs that might try to hitch a ride indoors and visit the rest of your plants.
4. Find an indoor spot with the best light you can give, away from air vents.
5. Watch that your trees are adjusting to the new spot - Personally my biggest concern is a placement so close to a southern or western window that the trees burn. I've seen it happen....because I've done it.
6. Don't panic if they drop leaves. It is almost inevitable as your trees adjust to the change in environment.
7. Be patient waiting for new foliage - I have owned chinese elm, bougainvilleas and pyracanthas that took a few months to regrow their leaves. If you have one of these- take your lead from the tree and move it to a slightly cooler spot out of the light for at least a month and let it rest- but check the soil and try to keep it damp.
Pay close attention to your trees while they are inside and really be careful about your watering. The light levels are going to decline until near the end of February when they will start to pick up again. That means not only are the days shorter, but the light reaching us is coming through at a different angle that affects it. For example, the sun at noon in December is nowhere near as strong as the sun at noon in June.
Another HUGE environmental change will be humidity levels which are lower indoors to start with and once the central air goes on will continue to plummet. Did you know that during the dry season in a rainforest the humidity drops to about 77% and the typical home in winter is 30-40%. Do you see that problem? I'm very sure it kills a lot of plants by late winter. Misting and pebble trays only help a little, a locally placed humidifier would be best.
OK, I'm wandering off into new topics (as usual) but the key message for now is -It's time to bring your trees inside.