Best Fertilizer for Bonsai Plants: Homemade, Organic, Natural, Compost, NPK, Liquid, How and When to Apply

Bonsai is not a specific species of a tree but a term used to describe any tree or bush plant that has been carefully grown and pruned to resemble a fully grown specimen. Fertilizers contain essential nutrients such as nitrogen, phosphorus, potassium, and trace minerals present in healthy soils. These nutrients are needed to make healthy soils and grow healthy plants. Nitrogen is for leaf production, phosphorus and potassium for root, flower production, general strength, and good health.

These fertilizers mostly contain balanced formulations and can be for everyday purposes, not only for Bonsai plants. You can use them on trees, shrubs, lawns, flowers, and vegetables that are not a problem with the soil. It is of utmost importance that you fertilize your Bonsai tree. Since Bonsai trees are usually confined to a pot, they cannot spread their roots in search of moisture and nutrients like a regular tree. Let’s find out the best fertilizer for Bonsai plants.

It will be up to you to provide all the nutrients Bonsai plants need. These nutrients need to convert carbon dioxide and water into food for your Bonsai. For this reason, you must use a good quality fertilizer to reduce nutrients in the soil and top them up. The nutrition of your Bonsai is most important for its good health. Note that fertilizer is only an alternative source of essential nutrients in healthy soils. Fertilizer breaks down into the soil by dissolving in water or microbial process. As a result, it releases nutrients in a form that can absorb plant roots.

Best fertilizer for Bonsai plants

Homemade fertilizers for Bonsai

Coffee grounds – Coffee grounds are a common substance found in compost piles, but they can also be suitable for Bonsai. Coffee grounds contain nitrogen, which Bonsai likes. So, using a little on your plant is a great way to give it extra nutrients. Using coffee grounds on its Bonsai soil helps maintain water and air and can even act as fertilizer.
Eggshells – Eggshells are a great way to add calcium to the soil around your Bonsai tree. Calcium is a desirable nutrient for almost any plant, making the soil prosperous and your Bonsai tree.

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Compost manure for Bonsai

Compost – Using compost on a Bonsai tree is a good idea. Compost supplies Bonsai with essential nutrients. So, it would be beneficial to add some ingredients to your soil.
Manure – Chicken manure is an excellent resource because it has the highest NPK ratings compared to all other organic substances.

Organic fertilizers for Bonsai

You can use organic fertilizers as an alternative to chemical fertilizers, such as rapeseed cake or different mixtures of bone, blood, cottonseed, fish emulsion, etc. Usually, the cake of these fertilizers is placed on the soil’s surface, and water is given through them. So, the soil gets a small dose with every water. These fertilizers must be broken down by the soil bacteria used by the tree, so they work a little more slowly.
Mix 9 cups cottonseed meal, 4 cups bone meal, 2 cups fish meal, 3/4 cup kelp meal, 4 cups fish emulsion, and 1 cup liquid fertilizer to make balls. Adjust the liquid amount so that the mixture is made by hand in the balls. These balls, made from fertilizers, allow nutrients to be leached in a growing medium during the water.

Liquid fertilizers for Bonsai

Seaweed – It is better to give moderate water in spring and summer but very little in winter. Use organic liquid fertilizer or seaweed fertilizer and fertilize Bonsai once every two weeks.
Epsom salt – Magnesium helps in the growth of any plant. It is also suitable for Bonsai’s development. Bonsai plants are commonly known for their thick roots and branches that the Epsom can help produce salt. Generally, spraying salt on leaves or leaves during the growing season allows Bonsai to grow faster.
Fish emulsion – It is also good to add water-soluble fertilizer (fish emulsion) to the spray water while misting the leaves. Overfertilization should be avoided, as it can burn leaves.

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Natural fertilizers for Bonsai

It would be best to fill wet pine bark mulch around the sides of the pot inside the hole. Then place an upper lining of pine bark mulch on the soil surface of the Bonsai pot so that you can make it along the surrounding soil line. Pine bark meets a few purposes; it protects the tree from water and makes it easier to get out of the ground later.

Commercial fertilizers for Bonsai

NPK ratio

However, Bonsai is limited to tiny containers which contain very little soil. Therefore, once the plant has used the immediately available nutrients, it has no way of branching out to find more. Fertilization replenishes the depleted Bonsai mix and gives your plant the nutrients needed for health and growth. All fertilizers have an NPK ratio and are represented in numbers. Based on the type of tree, soil, and time of year, every fertilizer has varying proportions from each other.

Indoor Bonsai plants need to be fertilized throughout the year, while outdoor Bonsai plants may need to follow a specific schedule to feed them. Indoor Bonsai, tropical and subtropical trees, require balanced fertilizer throughout the year. For outdoor Bonsai trees, you use fertilizers with various proportions of NPK depending on the weather.

In spring, use a high nitrogen fertilizer with an NPK ratio of about 10:6:6. Next, use balanced fertilizer in summer, with an NPK ratio of about 6:6:6. And finally, use low nitrogen fertilizer in autumn; the NPK ratio is about 3:6:6. If you want to encourage your Bonsai to flower, try using phosphorus-high fertilizer with a ratio of 6:10:6 NPK. Old Bonsai trees prefer a low intake of nitrogen.

Bonsai fertilizer schedule

You’ll need to fertilize your Bonsai throughout the growing season, usually from early spring to mid-autumn. Most outdoor Bonsais should not be fertilized in winter as it will encourage growth which should not happen as the tree should be inert. However, you can regularly fertilize indoor Bonsai throughout the year. Using different fertilizers, you can control the growth and development of your Bonsai.

Many Bonsai gardeners apply a Bonsai fertilizer to promote leaf and boost growth, high in nitrogen in early spring. Find one with a ratio of about 10:6:6, but don’t use this mixture throughout the growing season, as growth will be speedy, and the tree will need a lot of pruning to maintain its shape and style. Once the tree comes out of inactivity and early growth is encouraged, it is recommended that you use a balanced fertilizer in the summer months, with an NPK ratio of 6:6:6. One of the prominent roles of potassium is to prepare the plant for winter.

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In early autumn, switch to a fertilizer that is low in nitrogen and high in phosphorus and potassium, which will slow or stop growth so that the tree can enter its inactive phase. In addition, a mixture of 3:6:6 will help strengthen the leaf and root system so that the plant can withstand cold temperatures. If you have an old tree that has already been styled, you’d like to use one with a balanced fertilizer or slightly less nitrogen content throughout the growing season because you don’t want to stimulate the tremendous spring growth.

Bonsai plants are grown in a container means it needs to be fed regularly compared to most houseplants and decorative plants. Your Bonsai plant may stop absorbing nutrients during late summer and early fall. As your Bonsai growth begins to slow down, you need to cut down on feeding only once a month.

Deciduous Bonsai tree – You should fertilize it weekly during the growing season. It would be best if you stopped after its leaves fall. Some enthusiasts find it unnecessary to fertilize during the winter months, while others can give monthly fertilizer using fertilizer containing low nitrogen content.

Conifer Bonsai trees – You should fertilize this type of Bonsai tree weekly during its growing season. It would be best to fertilize it a few times during winter but use a low quantity of fertilizer.

Tropical and subtropical Bonsai trees – During the growing season, you should fertilize these types of Bonsai trees at a minimum weekly. In addition, bonsai trees should be fed monthly from fall to spring.

It would be best not to fertilize inactive and sick Bonsai trees. Before buying and applying fertilizer, you can understand the types of the tree as there will be different needs for different types. Growing young trees will require more help; you will need more fertilizer. The opposite happens with older trees requiring less fertilizer, especially when not training them. You should never apply fertilizer on dry soil. So, you should constantly water your tree before fertilizing.

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Frequently asked questions about fertilizers for Bonsai plants (FAQ)

Can I use Miracle-Gro on my Bonsai tree?

It may not be the best idea; Miracle-Gro fertilizer contains a lot of nitrogen for Bonsai. Generally, Miracle-Gro fertilizer can be very hard for the roots of the Bonsai tree, which can damage your plant.

Is there a time when I should avoid fertilizing my Bonsai?

The essential rule about fertilizing is never to feed a tree under stress. It would be best to never feed a new, dry, or tree during inactivity. After the repotting, leave Bonsai alone for at least a month before starting feeding again.

Is vermiculite suitable for Bonsai?

All Bonsai plants thrive in a high humidity environment; adding vermiculite to the mix bases of your Bonsai plants is a wise choice you can apply. Many Bonsai gardeners combine vermiculite with peat moss to enhance the root growth of Bonsai plants.

Can I use cactus soil for Bonsai?

You can use cactus mix for Bonsai due to its ability to maintain water. In addition, the soil of the cactus consists of inorganic matter, which is wonderfully suitable for growing Bonsai.

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Is peat moss suitable for Bonsai trees?

It keeps the water very quickly for a long time. It is better to mix peat moss with overall material to provide more drainage and prevent competition, as peat moss can be hard when dry leaving less space for root movement.

How long do Bonsai trees survive?

A Bonsai tree can easily live more than 100 years old under the right circumstances. Some can stay for centuries, up to a thousand years.

Why are my Bonsai leaves turning yellow?

The common reason for yellow leaves is more water. Unfortunately, too much water also causes root rot, and the tree may not be able to get enough nutrients.

Why is my Bonsai tree losing all its leaves?

The main reason for leaving Bonsai leaves is improper maintenance. It can include overwatering, underwater, insufficient sunlight, disease, and pest attacks.