Bonsai Trees need to be fertilized because most soil does not provide the essential nutrients required for optimum growth. Even if you are lucky enough to start with great bonsai soil, as your plants grow, they absorb nutrients and leave the soil less fertile. By fertilizing your bonsai, you replenish lost nutrients and ensure that it has the food they need to flourish.

Learn More - Bonsai Fertilizer FAQ Answered

There are six primary nutrients that plants require. Plants get the first three-carbon, hydrogen and oxygen-from air and water. The other three are nitrogen, phosphorus and potassium.

To supply your bonsai with a continual supply of essential plant nutrients it is necessary to regularly apply fertilizer. It is far more important that a fertilizer with the correct nutritional balance is chosen. Regardless of the type of fertilizer you buy, it will be comprised of an NPK value. With Bonsai, using the right type of fertilizer is very important.

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Nitrogen [N] 

Of all the nutrients absorbed from the soil, nitrogen is the most important needed for growth. It promotes strong growth and dark green foliage. It is used quickly and is easily leached out of the soil. A nitrogen-deficient tree will be light green or yellow, with its older leaves affected before the younger ones. Nitrogen controls the growth of the leaves and shoots in a plant. Too much nitrogen and your bonsai will develop large, very dark green leaves and delays the production of blossom and the maturation of the wood. If it is lacking, the new leaves take what little there is and the older leaves turn yellow and fall off. While some nitrogen comes from the atmosphere, most of it comes from fertilizers that must be absorbed through the roots.

Learn More - Basics of Bonsai Fertilizing

Phosphorus [P] 

Phosphorus encourages the growth of roots and flowers. Unlike nitrogen a plant will not take up more phosphorus than it needs. Phosphorus plays a key role in the respiration, photosynthesis and the transfer of energy within cells and tissues. It stimulates root branching and the production of root hairs, and helps the tree mature more rapidly. Leaves of plants suffering from phosphorus deficiency turn a dark green on top and red to bronze underneath.

When applied at the beginning of summer for about two months, in the correct quantities for bonsai, will improve the amount of blossoms, as well as the quantity of the blossom.

Potassium [K] 

Potassium is necessary for photosynthesis. Without photosynthesis, plants starve. Potassium also improves the rigidity of trunks and helps plants overcome adverse soil conditions. This helps in the maturing of the wood and increases the absorptive capacity of the roots; it makes the plants more robust overall. 

Related Article - Why and When to Fertilize Your Bonsai

It is important when purchasing fertilizers that the three major elements are balanced. The numbers on a bag of fertilizer tell you the percentages of available nitrogen, phosphorus and potassium found in the bag. So 4-4-4 fertilizer has 4-percent nitrogen, 4-percent phosphorous and 4-percent potassium.

Don't fertilize sick or unhealthy bonsai trees, and never fertilize dry soil. Fertilizing should always be combined with normal watering practices.

We hope this was helpful, but want to remind you that these are really only the basics for fertilizing your bonsai. For more information, please contact your local bonsai dealer.


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