To maximize growth and tree health, your tropical bonsai should be outside during the summer months, getting the most of the warm temperatures and full sun. But before the temperatures drop—most tropical bonsai will not tolerate temperatures below 40 to 45 degrees Fahrenheit for any length of time without some damage—it is a good idea to slowly move your trees into lower light conditions. This will prepare your trees for the conditions in your house, and result in less leaf drop when they are moved inside. During this time you should also decrease the feeding of your tropical trees, slowing down the growth.
There are four things to consider when picking a spot in your house for your tropical bonsai.
Lighting: Even if you have a south-facing window, most trees are going to require supplemental lighting for the winter months.
Heat: Trees should be in a warm spot in your house, but should never be subject to hot, dry forced air or radiant heating.
Humidity: Due to the dry nature of our heating, supplemental humidity should be provided. Humidity trays, spraying your trees daily with a spray bottle, and humidifiers are all good ways of increasing the humidity around your trees.
Watering needs: Tropical trees tend to use less water in the winter. Over watering can cause root rot and a decline in tree health.
The preparation for hardy trees (both deciduous and evergreen) starts long before they are put away for the winter.
In late summer to early fall, you should stop feeding your trees with nitrogen. Nitrogen—the “N” in N.P.K.-based fertilizers— stimulates foliage growth. As fall approaches, we want to start sending energy to the roots, so using a “bloom” fertilizer with higher phosphorous and potassium values (P and K) is important. This will feed the roots and strengthen the tree for winter. It will also provide the tree with the energy for the spring flush. In bonsai, it is important to be proactive rather than reactive. The things we do in the fall determine how trees respond in the spring.
The pre-storage work done on your trees is important.
Our winter cleanup on all deciduous trees entails the following:
Removing all the old foliage from the deciduous trees. This is most often done with tweezers to prevent any damage to the branches and next year’s buds. This step helps to prevent fungal disease forming on those leaves.
|Moss has been removed from the trunk pre-storage|
Cleaning the bases of the trunks, and removing moss and weeds from the soil surface. This prevents constant moisture from touching the trunks and allows better air circulation to the roots.
Performing minor pruning work.
The larger cuts will wait until spring when it is safer. All cuts are covered with “cut paste” to seal the wound and prevent disease and damage to the branch.
Tagging. Finally, each tree receives colored tags that indicate whether it needs repotting in the spring, has wire, needs wire, etc. These indicators are very important when managing about 250 trees!
Evergreen trees and pines get their own pre-storage cleanup.
Instead of removing leaves, we remove old needles on the pines. This is also done with tweezers, and needles are pulled in the direction in which they grow to prevent damaging the branch.
Some light pruning is done as well as cleaning the surface of the soil.
Proper winter storage will ensure that your trees wake healthy and ready to bud out in spring.