If you have a bonsai that needs to be dormant during the winter months, there are a number of techniques you can use during the dormant period. If you have purchased a new Bonsai, you should first find out what types of conditions have existed during previous dormancy periods.
This will help you match those conditions near your home as much as possible, to ensure a healthier plant.
If your Bonsai was wintered indoors with cool conditions, then you’ll need to create a safe outdoor area that can match these conditions as much as possible. Winterized indoor Bonsai are not used to outdoor elements in the winter, so you can’t simply place your plant outdoors hoping it’ll survive.
If you have room in your refrigerator, you can place your Bonsai in it during the dormancy period. If not, then you can also store your Bonsai in an unheated garage, shed or even under your porch. If you store your Bonsai under your porch during the winter months, then you should place it in a container that will keep most of the wind and all of the rodents away from your Bonsai.
If you live in an apartment, and don’t have access to a garage, shed or porch then you can pack your Bonsai in a cardboard box and place it on your balcony. Place Styrofoam peanuts around your Bonsai to keep it from shifting or falling over while being stored.
You should also remember that your Bonsai would need to be watered in the winter as well, to prevent it from drying out. It will not need as much water as it does in the spring or summer, but you will want to keep the soil moist to ensure that it does not dry out and die during the dormancy period.