Water and Fertilizer

I found this on Bonsai Boy of NY , my favorite Bonsai Store.

Practiced for centuries in China and Japan, bonsai is the reproduction of natural tree forms in miniature. Bonsai trees are living miniature trees which increase in beauty and value as they mature over the years.

How often should I water my bonsai tree?
Unlike a houseplant, bonsai trees use a "free draining" type of soil because their roots cannot tolerate "wet feet". In addition, they are grown in significantly less soil and, therefore require more watering. Factors such as tree location, temperature, lighting conditions, quantity of soil used, and the changing seasons will determine the frequency of watering. You can get to know when your tree needs to be watered by observing the foliage, testing the soil with your index finger just below the surface, or just by the weight of the pot. (The drier the tree, the lighter it will feel.) To take the guesswork out of watering, we recommend an inexpensive moisture meter which works very much like a thermometer. Insert it into the soil and the movement of the needle will tell you if it is time to water.

How often should I fertilize my bonsai tree?
Because bonsai trees are cultivated in limited amounts of soil, adequate feed is very important. As a general rule, a small amount of feed is given in the spring and a larger amount in the fall. Feed for bonsai should contain three principle ingredients; nitrogen, phosphoric acid, and potash. It is also a good idea to use a fertilizer containing "chelated" iron. Water before fertilizing your tree and then apply at half the strength recommended by the brand's manufacturer. We rotate the use of brands since different manufacturers add different amounts of trace elements and minerals. We also add Superthrive which is a vitamin supplement to our fertilizer mix. You may find it simpler and easier to use slow release fertilizer granules (placed over the soil) whose nutrients are released with each watering.