Choosing a Container
Your planting should be balanced and proportionate to its container in order to create visual harmony. Use the following standards as a starting place; then experiment to create a bonsai that is uniquely yours.
Although pot size is determined by the tree’s height, branch spread, and trunk diameter, most bonsai pots are very shallow. A bonsai pot should have a length slightly more than two-thirds its height, and a depth about equal to the diameter of the plant’s trunk at its base.
Once you’ve determined size, choose a container that reflects your desired aesthetic. Stoneware is ideal, since it’s usually unglazed and available in muted shades, which enhance the color of the bonsai’s foliage without detracting from the creation as a whole. For outdoor plants, steer clear of terracotta, which is prone to freezing and will crack easily.
"A bonsai can never be a finished work of art because it will always be a living piece of nature." —John Yoshio Naka, Bonsai Master
First, place a fine screen over the holes in the bottom of the container and lay a thin layer of gravel on top of the screen to promote drainage. Next, add a layer of soil—don’t use standard commercial potting soil, as it holds too much moisture and lacks adequate air pockets.
Soil for bonsai must retain some moisture, but should drain well and hold air between the soil particles for roots to grow into. Experienced growers use an inorganic blend of equal parts pumice, lava cinder, and akadama, an ingredient imported from Japan. A four-gallon bag of this mixture retails for approximately $19, and is available along with other soils suitable for bonsai at Wee Tree Farm and other bonsai specialty nurseries (see Info & Supplies on page 2).
Once your pot is ready, place the tree slightly off center and toward the rear of the container, placing the densest foliage toward the back to give the planting more depth. Twisted roots add visual interest and the appearance of age to the bonsai, so keep them exposed just above the soil level.
Bonsai trees need to be repotted when the roots fill the container. Growth will slow as the plant matures, and it will need to be repotted less frequently. Apply fertilizer to keep your bonsai healthy and strengthen roots without encouraging top growth. Use a diluted liquid fertilizer weekly during the vigorous growing season (April to October) and monthly when dormant. Keep in mind that it is better to fertilize too little than too much.