8 Best Bonsai Fertilizers | How And When To Apply To Bonsai Trees

The art of cultivating Bonsai trees is as old as recorded human history. With the earliest documented practices dating back as far as 500 BC, in ancient China. Fast-forward to the 12th century, when Buddhist monks adopted this perennial art form as a way to adorn their temples with elements of the natural world. Today, this practice of bringing the outdoors inside continues as Bonsai enthusiasts, worldwide, carry the cultivation of these beautiful little trees into the 21st century.

Bonsai is not a specific genus of a tree but rather a term used to describe any tree or shrub sapling that has been carefully grown and pruned to resemble a fully-grown specimen. While bonsai cultivation is both an art and a science, here we’ll discuss an important part of this time-honored practice. Namely, which is the best bonsai fertilizer to keep your curated beauty healthy and thriving.

Choosing The Best Bonsai Fertilizer

A couple of things to keep in mind when choosing the best feed for your bonsai are the age of your tree and the kind of soil it grows in. These two factors will determine the right NPK and application method for you and your artful tree.

Types Of Bonsai Fertilizer

The use of a slow-release (granules and spikes) or a quick-release (liquid) is merely a matter of personal choice and what makes your bonsai adventures more successful and enjoyable. Let’s take a look at the difference between them.

Fertilizer Granules

Granules are a heavily concentrated, slow-release method,  providing consistent nourishment for several months at a time. Often no watering is needed to activate and is less likely to leach out with consistent watering. Typically dug into the soil around the plant’s base, this type is well-known for its ease of use and no-mess storage.

Fertilizer Spike

Slow-release spikes are one of the easiest to use, especially if you have more than one bonsai tree. Pre-measured and compact for easy storage, they carry far less risk of run-off and root burn. This method also carries the added benefit of stimulating an increased resistance to disease and pests.

Liquid Bonsai Fertilizer

Liquids can be more economical than the previous two and are faster acting as well. Nutrients are immediately carried to the root system through the soil while also keeping the pH levels in your soil balanced. However, caution is recommended, as over-feeding could lead to root burn.

Bonsai Tree Fertilizer Ratio N-P-K

The best bonsai fertilizer for your tree will contain an ideal combination of three key macronutrients to keep your treasured sapling healthy and thriving. These are nitrogen (N) – for consistent, healthy growth of stems and leaves, phosphorus (P) – which supports strong root development, and potassium (K) – which contributes to a strong, overall structure that can withstand constant pruning.

The NPK formula is displayed as three numbers on the label. These numbers represent the proportions of nitrogen, phosphorus, and potassium. For example: A 24-8-16 NPK contains 24% nitrogen, 8% phosphorus and 16% potassium.

Synthetic Vs Organic Bonsai Fertilizer

Another point of personal preference is choosing between an organic or synthetic (inorganic) fertilizer. Knowing your end-result expectations and having a basic understanding of the difference can help you make a solid fertilizer choice.

Organics are usually plant or animal-based while inorganics are manufactured with minerals and synthetic chemicals. Organic feeds generally contain lower levels of nutrients but can nourish your bonsai for a longer period of time. While synthetics typically produce faster, more robust growth.


8 Best Bonsai Fertilizers Reviews

After extensive research in a broad range of review forums, not to mention giving bonsai-growing a try for myself, I’ve gathered 8 examples of the best bonsai fertilizers available on the market right now. Allowing you to make the best choice for your curated trees and give them the boost they need, without worry.


1. Leaves and Soul Bonsai Fertilizer Pellets 18-6-8

Leaves and Soul Bonsai Fertilizer Pellets

This first, slow-release option comes from the brand Leaves and Soul. The nitrogen-abundant NPK and essential nutrients nourish my bonsai trees from root to tip. Responding very well to these pellets, with vibrant color and increased leaf production. Feeding was a snap, too, as I only needed to apply it once every 6 months.

I have recently acquired a Deshojo Maple which can be particularly susceptible to root burn if over-fertilized. Plus, it also needs watering every day while in the growing season. These pellets held firm in the soil despite the regular watering and their gentle, slow-release formula meant no signs of damaged roots. The leaves of these bonsai are truly stunning and I’ve enjoyed the subtleness of the leaf color changes right through until the Fall. View Leaves And Soul Bonsai Fertilizer here.

How To Use: Insert pellets around the base of your tree every 6 months. I have a 4-inch pot and followed the manufacturer’s recommendations by adding half a teaspoon of pellets to the soil per application.

Customer Reviews: Because so little is needed for such great results, this pellet option comes in an easy-to-store 5 oz resealable bag which bonsai growers seem to absolutely love. Granting this feed choice from Leaves and Soul an impressive 4.6 out of 5 stars and my choice and best buy.

Pros      

  • Nitrogen-rich NPK + essential micronutrients.
  • Compact, resealable bag for easy storage

Cons

  • Slightly higher price point than other options

2. Perfect Plants Bonsai Fertilizer Pellets 18-6-8

Perfect Plants Bonsai Fertilizer Pellets

Next is this easy-to-apply, time-release option from Perfect Plants. The nitrogen content in these pellets is good for both ailing older trees and new starter kits and one application is all you need for enriching the soil and ensuring root growth for a full 12 months.

My inherited Chinese Elm specimen is over 20 years old. It had started to wane recently and I couldn’t figure out why. With just one gentle infusion, it responded very well with fewer leaves falling followed by healthy, new growth. I would definitely recommend putting some new life back into an aged bonsai tree especially if you know it has been in the same soil for some time.

How To Use: Distribute 1 ounce of pellets around the tree’s base and push them into the soil. Water thoroughly to activate. Click here for Perfect Plants Bonsai Fertilizer Pellets from Amazon.com

Customer Reviews: Consumers are happily reporting how well their ailing bonsai trees are responding to this product after just two weeks of application. Giving novice and experienced growers alike the successful and bountiful experience they hoped for. 4.5 out of 5 stars.

Pros      

  • Just one application lasts for 12 months
  • No risk of root burn or run off

Cons

  • May not be appropriate for use in nitrogen-rich soil

3. Perfect Plants Liquid Bonsai Fertilizer 9-3-6

Best Bonsai Fertilizers

If fast-acting is what you need, Perfect Plants also offers a soluble liquid option with the same nitrogen-focused NPK that encourages vigorous growth and allows for frequent pruning.

I was asked recently for a recommendation for feeding a Larch Bonsai Tree. These particular species don’t tend to need too much feeding but they do need regular pruning due to their triangular shape so I suggested this liquid feed. A diluted formula is a good way to maintain control over the dosage and the watered-down solution means less chance of root burn.

How To Use: Combine 1 tsp for every 4 liters (1 gallon) of water used. If you have a small collection of bonsai you are unlikely to need to use one gallon. I recommend making up a one-gallon batch, using whatever you need, and then keeping it in a safe place until the next time you need it. It’s a good way to reduce waste. For more about Perfect Plants Liquid Bonsai Fertilizer click here.

Customer Reviews:  It’s true that good things come In small doses, as users of this liquid option can attest. Even as little as one-quarter teaspoon results in lush growth in record time. And given the size of the bottle, it has fantastic value for money. Awarding this liquid option 4.4 out of 5 stars.

Pros      

  • Great for an instant boost of nutrients
  • Fast results and economical

Cons

  • Overuse may result in root burn

4. Dyna-Gro | Bonsai-Pro Liquid Plant Food | 7-9-5

Dyna-Gro | Bonsai-Pro Liquid Plant Food

From Dyna-Gro comes my second quick-release pick. A 7-9-5 NPK with an additional 16 essential minerals and micro-nutrients raises the bar to professional-grade results. I had chosen to add some natural compost to a couple of bonsai, so they really didn’t need a lot more nitrogen. The higher phosphorus content in Bonsai-Pro resulted in more effective nutrient uptake without the risk of root burn.

How To Use: I kept the ratios in line with the manufacturer’s recommendations and forum comments from users whose Bonsai had suffered dropped leaves by mixing just one-quarter of a teaspoon per one gallon of water. I kept the one-gallon quantity in a watering can (on a high up shelf) and used it with every watering rather than making a fresh quantity. Click here for Bonsai-Pro Liquid Plant Food from Amazon.com

Customer Reviews: Growers of some of the most challenging bonsai tree types are raving about the results they get from this product.  Saying “Bonsai trees usually deplete the soil of all its nutrients by a certain age. This feed replenishes all of it”. Granting this option 4.5 out of 5 stars.

Pros      

  • Professional grade results with just a small amount
  • Including 16 essential minerals and macronutrientsFast results and economical

Cons

  • Incorrect dosage may result in foliage loss

5. BioGold Bonsai Fertilizer Pellets 5-6-3

No need to push these organic triangle-shaped pellets into your soil. They sit right on top and stay in place as they slowly release vital nutrients and beneficial bacteria to your bonsai. Versatile enough for other houseplants as well, this well-balanced formula actually resulted in a higher number of blooms on my flowering Serissa bonsai tree.

How To Use: Scatter the recommended number of pellets around the soil and water thoroughly to activate. Repeat every two months. See BioGold Bonsai Fertilizer Pellets here.

Customer Reviews: Houseplant and bonsai collectors are impressed with the healthy roots, foliage, and blooms that result from this versatile, organic option from BioGold giving it 4.6 out of 5 stars. Careful though, my dog is highly attracted to their ‘organic’ aroma.

Pros      

  • Versatile enough for all houseplants
  • Includes beneficial bacteria for healthy plants

Cons

  • May exhibit a slight organic odor

6. Bonsai Tree Fertilizer Tons of Micro Nutrients 18-4-10

Bonsai Tree Fertilizer Tons of Micro Nutrients

If granular feeds are more your style, this all-purpose in-organic bonsai fertilizer may be the one for you. The generous amount of nitrogen in the NPK showed really positive results with lots of new growth appearing on my Chinese Juniper after a sudden bout of dieback.

A word of caution, far less may be needed than is recommended on the container. So, I suggest starting out with just a fraction of that. Then, increase from there if needed.  Click here for Bonsai Tree Fertilizer Tons of Micro Nutrients

How To Use: Sprinkle with a small percentage of the recommended dose around the soil once a month. My specimen stands in a 3-inch pot and the recommended half a teaspoon seems excessive for this sensitive bonsai. Once you have sprinkled the required amount, continue to water as normal.

Customer Reviews: Despite the apparent need for an adjustment in dosage, customers are very pleased with the vigorous growth and vibrant foliage color resulting from the use of this product. Solid recommendations in all the review forums studied. 4.5 / 5 stars.

Pros      

  • Promotes a strong root system for healthy growth
  • Sold in a large container that lasts a long time. Great value for money

Cons

  • An adjustment in dosage may be needed

7. Bonsai Resource Center Liquid Fertilizer for Bonsai Trees 3-3-3

Bonsai Resource Center Liquid Fertilizer for Bonsai Trees

For bonsai trees that are planted in nutrient-poor soil, this liquid feed from The Bonsai Resource Center is organic and gentle enough to infuse soil and your precious bonsai tree with a perfectly balanced NPK, humic-fulvic acid, and sea kelp extract. What’s more, it carries little or no risk of root or foliage burn. Click here for Bonsai Resource Center Liquid Fertilizer from Amazon.com

I’ve been using The Resource Center’s Monstera Fertilizer on my Monstera Adansonii for over a year now. These guys are great at getting the right balance of macronutrients in a gentle formula so as not to harm the roots of plants. The slightly higher price point is worth it in my opinion. Bravo!

How To Use: Mix one teaspoon per one cup of water with every watering.

Customer Reviews: Gardeners looking for a simple, organic option love the gentle introduction of vital nutrients that this option provides. Especially with plants that were at risk of failing. Awarding this liquid option 4.3 / 5 stars.

Pros      

  • Free of Urea and other harsh chemicals
  • Provides a gentle infusion of essential nutrients with any risk of burn

Cons

  • Slightly higher price point than other options

8. Bonsai Plant Food Organic Liquid Fertilizer

Bonsai Plant Food Organic Liquid Fertilizer

My final pick is this wonderfully organic liquid option from The Grow Co. A concentrated blend of essential macro and micronutrients are quickly sent to the roots, trunk, branches, and foliage for vibrant, healthy growth. It’s also great as a fertilizer for indoor bamboo too.

How To Use: Mix 2 teaspoons into 1-gallon water for balanced dilution. Then, water regularly.

Customer Reviews: Very well received by the organic growing community, bonsai gardeners report strong and vigorous growth over time. And have peace of mind knowing that they aren’t introducing any harsh or harmful chemicals to their delicate trees. 4.6 / 5 stars.

Check out Bonsai Plant Food Organic Liquid Fertilizer at Amazon.com

Pros      

  • Works well with all types of Bonsai
  • No harsh chemicals or additives

Cons

  • Exhibits a slight odor

How To Fertilize Bonsai Trees

As we’ve seen, there are many solid feed options out there and the best bonsai fertilizers for you will depend on your tree’s age, its current state of health, and the condition of its soil. However, where it’s located, when to fertilize, and how often are important points too.

Fertilizing Bonsai Trees Indoors Vs Outdoors

Bonsai trees are commonly grown indoors. But, given that many bonsai are simply smaller versions of outdoor trees, expert growers do recommend they be occasionally exposed to outside environments. One thing that indoor and outdoor-grown bonsai have in common is that they all grow in pots. Making them fully dependent on us for their nutrients intake.

How Often To Fertilize Bonsai

How often to feed your tree will depend on the method of application you choose. Granular, pellet, or liquid. Slow-release methods only need to be applied every few months where quick-release or water solubles are recommended with every watering.

When To Fertilize Bonsai

Bonsai change from moderate feeders to light feeders as they mature. Young trees should be fertilized throughout the full growing season, early spring to mid-autumn. Older, more mature trees require less and should be fertilized based on season, stage of growth and development, and current state of health.

Best Bonsai Fertilizers Final Thoughts

Bonsai fertilizers can either provide slow, time-released nutrients or an instant boost of goodness. The choice you make on which to buy depends on a combination of factors that are unique to your particular bonsai specimen. Whether you’re looking for a specific feed to improve the richness of your soil type or to encourage new or failing growth to your tired-looking bonsai, you can be sure to find the fertilizer you need from my shortlist of outstanding products.

If you’re really still confused and just want a recommendation I would suggest Leaves and Soul Bonsai Fertilizer. A great pellet-based option that offers vitality to foliage and roots but will help to minimize the risk of root burn.  My second choice, again a fertilizer pellet and also a slow-release option from Perfect Plants that’s a great option for ailing bonsai trees.

Alternatively, if it’s a quick fix, good value option that you need, give Perfect Plants Liquid Bonsai Fertilizer a try. It offers a high nitrogen formula to improve the nutrient value of the soil, but it can be diluted and will stretch further if you have a collection of bonsai trees to feed.