There’s a cold front moving in this week. If you haven’t done so already, it’s definitely time to bring your tropical trees indoors! While some of the tropicals may take temperatures down into the high 30°F’s for a day or two, there’s no benefit involved. Also remember that a tropical bonsai will need as much light and humidity as you can provide during the winter, and don’t forget to water. The levels of light indoors are not as strong as those outdoors. Don’t be alarmed if your ficus start to drop leaves in their new location. As long as you’re not letting them get too dry or keeping the soil from oxygenating by watering too frequently with a water-retentive soil mix, it’s probably just a normal reaction to change in conditions.
Hardy trees should be allowed to experience the cold. It’s actually quite beneficial for them to get hit with some cold as it puts them into dormancy. This includes Chinese Elms and Juniper Procumbens. Many of the hardy trees can take temperatures down into the 20’s, some even lower. Thanksgiving is usually the cutoff here in New Jersey. By then the bonsai should have had enough cold to tell them it’s time to go dormant, and can safely be tucked away, but we have purposely exposed some of our bonsai to much colder much later than November in order to get them to go dormant.
If you have any questions or concerns please ask!