Caring for a bonsai tree is an Asian art that originated in China. As a small tree restricted to a container, bonsai trees require frequent care and periodic soil enrichment. When selecting a fertilizer for your bonsai, reference your bonsai species with its nutrient and soil requirements to support its growth and longevity.
Selecting a Fertilizer
All bonsai trees are not the same, and their nutritional needs vary. There are organic and chemical fertilizers for bonsai trees, and they contain different ratios of nitrogen, phosphorus and potassium. The mixture of nitrogen, phosphorus and potassium supports leaf production, root growth and normal plant function, notes The-Bonsai-Tree.com.
Bonsai trees need the trace elements that naturally exist in outdoor soil, notes Brent Walston of Evergreen Garden Works Nursery. Select fertilizers for your bonsai that include trace elements such as calcium, copper, magnesium, iron, zinc and cobalt.
Avoid fertilizing your bonsai tree when it is under stress, such as after a pruning or when it has had too much or too little water or sunlight. Avoid fertilizing your bonsai tree in hot weather as the fertilizer may damage its roots.
Fertilize the tree during its active growing season when the tree will absorb and use the fertilizer most efficiently. Fertilize your bonsai tree in the early spring and again in late summer or early fall. Bonsai varieties have different fertilization needs and some may need fertilizing every two to four months. Dilute the fertilizer to half strength when your bonsai tree is in a weakened state from illness or lack of nutrition.
Fertilizers for bonsai trees are available in powder, capsule, tablet and liquid form. Slow-release fertilizers provide a steady supply of nutrients to the bonsai tree over time. Follow the manufacturer's instructions on how to use the particular type of fertilizer--incorrect application could harm the tree's fragile roots.
Adding the right fertilizer is not about feeding your bonsai tree. The right fertilizer will promote healthy root growth and assist the bonsai tree's internal food production. Over time, the roots of your bonsai tree will absorb all of the nutrients in the soil, and because it is not in its natural environment--where its roots can extend out into the soil for more nutrition--you must add fertilizers to the soil to maintain its nutritional balance.