Fertilizer is important to your tree’s health. Unlike a potted plant the soil in your bonsai pot will lose its nutritional content quickly. Every time you water a small portion is washed away. The 3 essential plant nutrients are nitrogen, phosphorous, and potassium. For general use it is important to keep these nutrients balanced. Such as a 10:10:10 or 15:15:15 ratio. The type of fertilizer used is not as important as the balance of these nutrients. Nitrogen helps produce protein which promotes leaf growth. Phosphorous encourages sap flow, increases disease resistance and promotes root growth. Potassium provides energy and promotes fruit and flower production.
Outdoor trees only require fertilizer during the growing season. Typically this is between March and the end of August. Indoor trees can be fertilized all year round. We recommend a pellet type fertilizer for the outdoor trees with supplemental liquid applications. We add pellets about every 6 weeks and apply a liquid fertilizer every two weeks. You may use pellets on your indoor trees, but they tend to have an obnoxious odor. Be sure to read the dosage amounts, more does not necessarily mean better. In fact too much could potentially cause unrepairable damage.
“Fertilizer does no good in a heap, but a little spread around works miracles all over.” Richard Brinsley Sheridan