Clay Pots & Trays for Bonsai
The pot or container in which the bonsai is placed is as important as the design of the tree itself. The containers should always have feet, allowing them to be raised up to make drainage easier. Also, a bonsai tree is never centered in the pot...typically the tree is placed at the rear of the pot. Pots with dull earth colors are usually best, although more colorful pots can serve their purpose. Whatever you do, don't use a pot that has glazing within, since this can prevent the roots from adhering to the sized of the pot and make them unstable.
Nonporous plastic pots and glazed ceramic pots may create watering or drainage problems. Therefore, these are not typically recommended.
Other bonsai container materials, such as metal or wood can present their own sets of issues, especially for novice bonsai enthusiasts. Since many metals tarnish, they may require periodic cleaning or polishing. If excess water is left standing indefinitely in the pot, it could corrode the metals. Plant roots that touch the sides or bottom of a copper pot, in particular, will die. This shouldn't radically affect the plant's health, since the remaining roots will live, but as a general rule of, copper should be avoided as a bonsai container for the optimum health of tree’s roots.
Stained or varnished, wood is usually nonporous. Untreated wood containers can be porous and, like clay pots, should be soaked before you plant in them. If drainage holes are present, place a waterproof saucer under the pot to catch excess water. If your wooden container is slatted, the sides may not be watertight. This could create a seepage problem that would be unattractive, as well as hard on furniture surfaces. It's best to use these containers as decorative sleeves rather than planting in them directly.