Best Bonsai Fertilizer and How to Fertilize

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The art of the Bonsai Tree is centuries old in both China and Japan. In the 13th century, it increased its fame when Japanese Buddhist monks visited China and adopted the practice, bringing it back to Japan. Now it is an internationally appreciated art with thousands of bonsai enthusiasts worldwide.

The Bonsai tree is not a specific tree species, but rather the art of taking a baby tree or sapling and pruning and training it to resemble a tiny full-grown tree. The art is in the tree remaining small throughout its lifetime as a small living sculpture.

An important aspect of the success of this art is the feeding of your bonsai tree, so it grows as a healthy tree. Good fertilizer can help provide healthy bonsai soil.

This article discusses the best bonsai fertilizers to keep your precious bonsai tree healthy and beautiful.

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5 Best Bonsai Fertilizers

1. Perfect Plants Bonsai Fertilizer Pellets

The Perfect Plants Bonsai Fertilizer Pellets are a time-release fertilizer in easy-to-apply pellets. An NPK ratio of 18-6-8 offers a generous level of nitrogen content that aids new baby bonsais and supports older bonsais that are ailing.

A noteworthy advantage of these pellets is that they are applied once a year and support root growth for an entire year. One ounce of these pellets is sufficient when placed around the base of the tree and pushed into the soil.

The first watering will activate them. These pellets have been repeatedly cited by satisfied customers when used for mature bonsais that are having problems.

Perfect Plants Bonsai Fertilizer Pellet Pros

  • One application annually lasts a full 12 months
  • No burning of root systems
  • Retains moisture
  • Natural ingredients

Perfect Plants Bonsai Fertilizer Pellet Cons

  • Should be avoided in soil beds already rich in nitrogen

2. Dyna-Gro Bonsai-Pro Liquid Plant Food BON-008

The Dyna-Gro Bonsai-Pro offers a quick-release liquid soluble plant food with an NPK of 7-9-5 and the addition of 16 micro-nutrients and essential minerals.

This fertilizer is higher in phosphorous, which helps the intake of nutrients without risking the burning of the root system.

The goal of this fertilizer is to replenish nutrients in the soil that have been depleted through drainage or consumed by the tree.

Dyna-Gro Bonsai-Pro Pros

  • Requires a small amount
  • Rapid results
  • Macronutrients
  • 16 essential minerals
  • Economical

Dyna-Gro Bonsai-Pro Cons

  • An error in dosage can result in leaf drop

3. Leaves and Soul Bonsai Fertilizer Slow-Release Pellets

These Leaves and Soul Bonsai Fertilizer Pellets are a slow-release option with a nitrogen-abundant NPK ratio of 18-6-8.

Produced in a convenient pellet form, they are applied as little as twice annually or every six months. They remain firm in the soil despite frequent, if not daily waterings. The slow-release method is gentle on root systems and contributes to increased foliage growth.

Sold in a resealable easy-to-store bag, ideal for Bonsai gardeners. Pellets are inserted at the base of the tree every six months.

Leaves and Soul Bonsai Fertilizer Pellets Pros

  • NPK is nitrogen-rich
  • Essential micronutrients
  • Resealable easy-to-store bag
  • Feeding every six months
  • Suitable for all Bonsai species
  • Urea-free

Leaves and Soul Bonsai Fertilizer Pellets Cons

  • More expensive

4. Perfect Plants Liquid Bonsai Premium Concentrated Fertilizer

If you need a fertilizer that acts quickly, the soluble Perfect Plants Liquid Bonsai Fertilizer is a great option. This liquid feed also boasts a nitrogen-heavy NPK of 9-3-6 to encourage healthy growth.

It is useful and effective for Bonsai trees that require frequent pruning. For trees that don’t require a lot of fertilizer, but that do need regular trimming, this fertilizer can be diluted to sustain pruning without overfeeding or risking burning root systems.

The recommended dosage is one teaspoon per gallon of water (or four liters). If you do not use a full gallon when feeding, you can store the remaining fertilizer until needed.

Perfect Plants Liquid Bonsai Fertilizer Pros

  • Great for quick boosts
  • Stimulates rapid growth
  • Economical

Perfect Plants Liquid Bonsai Fertilizer Cons

  • Exaggerated use can burn root systems

5. Houseplant Resource Center Bonsai Tree Liquid Fertilizer

Bonsai trees that have a soil bed poor in nutrients will appreciate this Houseplant Resource Center Bonsai Tree Liquid Fertilizer. It is gentile and organic, so it can be used to thoroughly water your tree’s soil bed.

This liquid soluble feed offers a perfectly balanced NPK of 3-3-3, eliminating the risk of root system burn or foliage burn. One teaspoon of fertilizer added to every cup of water is a good ratio mixture to avoid waste.

If you have an ailing bonsai tree, this is a gentle supportive option that can help revive the bonsai. 

Houseplant Resource Center Bonsai Tree Liquid Fertilizer Pros

  • Urea-free
  • No harsh chemicals
  • No risk of root burn
  • Gentle application of essential nutrients
  • Uses humic-fulvic acid and sea-kelp extract
  • Easy to use for healthy growth all year long

Houseplant Resource Center Bonsai Tree Liquid Fertilizer Cons

  • More expensive

Guide to Bonsai Fertilizer for Bonsai Trees

There are several things to consider when selecting the types of fertilizer to feed your bonsai tree. Keep in mind your bonsai tree’s age and the kind of soil bed that you grow it in. These are the principal factors that will determine the correct NPK ratio of the fertilizer to use and how you should apply the fertilizer for healthy growth.

What Are Bonsai Fertilizers?

Bonsai trees need nourishment to survive and thrive. They absorb necessary nutrients from the soil, which will eventually deplete the soil after a while. In nature, there are natural processes such as the decomposition of dead foliage that replenish essential nutrients in the soil.

Fertilizer replaces these natural processes in nourishing house plants that are indoor and container-grown. This is vital in the case of bonsai trees because they are generally planted in very shallow pots, so the soil is depleted quickly and there are not enough nutrients to nourish the bonsai.

Bonsai Fertilizer NPK Ratio

“NPK” represents nitrogen (N), phosphorous (P), and potassium (K). These are three key nutrients that are vital to the well-being of your bonsai tree and any good bonsai fertilizer will include a combination of the three.

Nitrogen is necessary for the health of leaves and stems, as well as for fueling growth. Phosphorous is needed for root development and aids in photosynthesis. Potassium supports general health and strengthens it, especially with continuous pruning.

A well-balanced fertilizer of all the basic nutrients will work for most types of bonsai trees. 

NPK will be indicated on the fertilizer label with three numbers that represent the proportion of the three nutrients. An example would be 30-10-10. This would signify 30 parts nitrogen to 10 parts phosphorous to 10 parts potassium.

Organic v. Synthetic Bonsai Fertilizers

The fertilizer market will also offer you a choice between organic bonsai fertilizer and synthetic bonsai fertilizer. Synthetic means inorganic and manmade. 

Depending on your personal preference and goals for your bonsai tree, and an understanding of the differences between the two kinds of fertilizer, you’ll be able to make an informed choice for the best bonsai fertilizer for your bonsai trees.

Organic fertilizers will consist of plant or animal-based ingredients. These may include fish, manure, or seaweed. Inorganic or synthetic fertilizers are made of synthetic chemicals and minerals manufactured in factories.

An organic fertilizer will feature lower levels of important nutrients, but have the capability of feeding your tree for a longer time. Synthetics will have higher nutrient levels that produce growth more rapidly.

If you decide on a synthetic fertilizer, it is recommended to avoid fertilizers that have urea among their ingredients. Urea is commonly found in fertilizers for nitrogen replenishment. However, due to the exceptionally high nitrogen level, they can damage bonsai trees cultivated in shallow soil beds.

Available Types of Bonsai Fertilizers

There are liquid quick-release fertilizers or solid, slow-release granules and spikes. No fertilizer type is better than the other. The liquid vs solid fertilizer choice will be a more personal choice as to which you prefer and is more convenient for you.

Bonsai Granule Fertilizers

Granule fertilizers are highly concentrated fertilizers that are used as a slow-release method. The granules provide the tree with nourishment over the course of several months.

Many granular fertilizer do not require any watering to activate them. Continued watering will also not interfere with their efficacy.

They are usually placed within the soil bed around the tree’s base. This solid fertilizer is not messy when used and is easy to use.

Bonsai Fertilizer Pellets

Fertilizer pellets are also exceptionally easy to use and a form of slow-release fertilizer. Pellets are particularly convenient if you possess more than one bonsai tree. These pre-measured fertilizers are compact in size and easy to store.

A nice advantage of using pellets is that the risk of root burn is far less than the liquid form of fertilizer. This fertilizer also helps stimulate the tree’s resistance to pest infestations and diseases or infections.

Liquid Bonsai Fertilizer

The choice of a liquid fertilizer is often more cost-effective than the other fertilizer types. Nutrients arrive immediately at the tree’s root system, and even when passing through the soil bed, pH levels are still maintained.

With liquid fertilizers, it is important to exercise caution, so as not to overfeed and risk burning the root system. Liquid fertilizer will require sticking to a schedule.

How to Fertilize Bonsai Trees

Fertilizing bonsai trees is not difficult. Follow the general instructions set for the type of bonsai tree and the fertilizer manufacturer for a healthy bonsai tree. 

  1. Read and follow the instructions that accompany your new Bonsai tree.
  2. Select the type of fertilizer you want to use. Liquid fertilizer can be used during every watering in the growing season. Make sure your fertilizer is urea-free.
  3. Create your feeding schedule for your Bonsai tree. Take into account the tree type and the growing season.
  4. Check your Bonsai for both over or under-fertilization symptoms. Also, take notice of what your Bonsai reacts well to. You’ll be able to figure out the optimum level for fertilizer. 
  5. Consistency is the key to your success. Plan your care program and stick to it.

When to Fertilize Bonsai Trees

For bonsais, regular feeding is vital for health. The frequency of feeding will depend on the season. Bonsais need to be fertilized from the beginning of spring and growing season through to autumn.

A few species will require occasional feedings even during the non-growing season during the winter months. Younger Bonsai will feed moderately for healthy root growth and then switch to light feeding at maturity.

Younger trees must be fertilized during the entire growing season, meaning from early spring through mid-autumn. Mature Bonsai require fewer nutrient feedings and can be fertilized based on the stage of growth, the season, and the tree’s state of health.

Fertilization Schedule for Different Bonosai Tree Types

  • Tropical and subtropical bonsai species will need to be fertilized weekly in the growing season. These trees will continue to grow year-round. They will need to be fed monthly from autumn until the beginning of spring.
  • Deciduous bonsai trees need to be fed weekly for the entire duration of the growing season. When bonsai tree leaves fall, fertilization should be interrupted because the tree has entered its dormancy period.
  • Conifer trees also need to enjoy a weekly feeding during their growing season. In winter, reduce the fertilization to once or at the most twice monthly. These trees do not enter full dormancy, so they will need nourishment as they continue to use nutrients even in the non-growing period.

Tip: As you water your bonsai tree in the non-growing season, you can add a gentile liquid fertilizer that has an NPK ratio of 3-3-3 to the water.

How Much Bonsai Fertilizer to Apply

As bonsai soil is mixed to drain water rapidly, nutrients will also drain away. Fertilizing is therefore vital to a bonsai’s survival. Liquid, granular, and pellet fertilizers will use different quantities depending on the product.

Follow the manufacturer’s recommended amount when using the fertilizer. Try their recommended fertilizing schedule and amounts initially and adjust depending on how your bonsai trees respond. 

Fertilizing Indoor and Outdoor Bonsai Trees

Bonsai trees are commonly cultivated indoors, but these indoor trees are miniature versions of outdoor bonsai plants.

Bonsai masters often suggest that every so often your bonsai tree should get exposed to the outdoors. Indoor and outdoor trees are both cultivated in pots, meaning that they need nutrients provided by gardeners.

Overfeeding Bonsai Tree Problems

Overfeeding your Bonsai can damage the plant roots. Symptoms to be on the lookout for include:

  • Topsoil has a crusty fertilizer layer
  • Slow growth
  • Leaves drop early
  • Foliage turns yellow or dies

If you have overfed your bonsai, it may die. Here are the steps to revive and try to keep your bonsai tree alive: 

  • First, remove any visible fertilizer.
  • Flush the tree’s roots with water to wash off extra fertilizer.
  • Prune damaged foliage.
  • Repot the bonsai in fresh, healthy soil mix. 
  • Wait one month before resuming fertilization.

When Not to Fertilize Bonsai Trees

Stresses bonsai trees should never be fed. Trees become stressed as a result of illness, lack of water, or recent repotting. After repotting, wait approximately a month before feeding the bonsai extra nutrients.

Bonsai Fertilizer Final Thoughts

Bonsai fertilizers can offer an immediate boost in nutrition in liquid form or slow, time-released nutrition in pellet form. There are various types of Bonsai fertilizers to meet both your Bonsai’s nutrition needs and your feeding schedule.

What nutrient form and release speed you choose in the end will be based on several important considerations that take into account your particular species of Bonsai, its age, level of development, and the amount of time you have to dedicate to the tree.

Learn more about bonsai trees with these articles:

Fast Growing Trees and Plants

Bonsai Boy Plants and Pots

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Written by:

Amy Walsh
Amy Walsh is a passionate indoor gardener, deeply engrossed in the world of houseplants and herbs. Her apartment is a lush sanctuary of foliage, reflecting her journey from hobbyist to devoted botanist. She's constantly exploring the latest in smart garden technology, eager to share her insights on nurturing green spaces indoors. Alongside her botanical pursuits, Amy enjoys connecting with nature and friends, continually enriching her lifestyle with greenery and growth.

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