Do You Need To Use “Bonsai” Fertiliser?

Fertilising a bonsai tree is really important and there are lots of fertilisers available to buy that will tell you that they are the best one for you tree.

The truth is, any fertiliser will do. There is no special formula designed for your bonsai tree. Of course there are different strengths and sometimes you may want one type over another, but I will go through that below.

What Is Fertiliser?

Fertiliser is simply nutrition for the plant. Fertiliser isn’t really food, as a plants make their own ‘food’ from carbon dioxide and light (through photosynthesis).

The plant uses various nutrients and minerals from the soil to make this process of photosynthesis more efficient.

Fertilisers are made of these nutrients, so they are added to make sure the plant has everything it needs to function well. Some fertilisers provide nutrients that the plant can directly use and others change the soil, so that the plant can make better use of what is already available.

Fertilisers are kind of like us taking vitamin supplements. We should have enough of everything we need through are food, but a little boost of certain minerals is always good.

Fertilisers can be synthetically made from chemicals or produced from organic substances. They can also be liquid or solid. This isn’t too important right now, as we are only looking at what “bonsai” fertiliser is in general.

(Some people use other things as fertilisers. You can Read about using coffee as fertiliser or what about Flower Food?)

What Is Bonsai Fertiliser?

The truth is bonsai fertiliser is no different than any other fertiliser.

It’s just marketing. They literally write “bonsai” on the label and then sell it to you for more money as you think it is some special formula.

I’ve actually seen a label on a box that said it’s perfect for bonsai …but also great for your house plants, garden plants and even your lawn.

The reality is you can use any fertiliser for bonsai. The name of the product is not important.

 What you need to look at is the NPK value and also decide what your goal is for your tree.

If the “bonsai” fertiliser fits these needs, then get it. There is nothing wrong with these products. Just don’t fall for the marketing and assume they are automatically the right product for you.

What Does NPK Mean On fertiliser Packets ?

All fertilisers are required to show these details on the packet. Basically it is the 3 main ingredients that fertiliser contain:

N is for Nitrogen, which is helps with a plants top growth.

P is for Phosphorous, which helps with root development.

K is for Potassium, which provides good overall heath and aids with how water is moved inside the plants stems and helps with fruiting and flowering.

Fertilisers focus on these three as they are the main nutrients a plant needs, although most fertilisers will also contain some of the smaller nutrients that are also required.  

You will see these three on the packet as something like this NPK 20-20-20. These numbers are basically the ratio of each nutrient and how much of the packet they make up.

The bigger the number, the bigger the amount.  This means certain fertilisers will be more beneficial for certain things or you can buy ones that are more balanced.

It’s really important to look at these numbers so you know what you are going to be giving to your tree and can decide if they fit in with your tree goals.

The Fertiliser You Need For Your Bonsai Depends On Your Goals

When you are growing a bonsai tree, you need to have some sort of plan for it. You don’t just keep a tree for a number of years and over time it develops into a bonsai. You need to have goals and you need to work towards them.

Usually bonsai trees start out in the development stage. The goals in this stage are usually things like getting a thicker trunk, creating a great root spread and getting some good strong branching. You generally aim to get the tree healthy and strong.

When you start to move into the refinement stage, your goals will change, you will start to want to build smaller, tighter ramification with smaller foliage. You will want your tree to slow down and not grow so aggressively.

You need to know what your current goals are, so you can work out what NPK you are going to give you tree.

This can get all a bit complicated, but just think about its simply and logically.

If you are trying to keep your tree small and refined, then it would be a bit silly to pump it full of nitrogen that is only going to make it grow like crazy.

On the other hand, if you have a young tree and you are trying to grow it bigger, you would probably want as much nitrogen as possible to maximize the growth and pump it up.    

knowing what your goals are will make sure you end up with the right fertiliser.

What Are Good Fertilisers For Bonsai (And What NPK Do They Contain)?

I will just go through some common fertilisers used for bonsai and show their NPK so you can start to get an idea of how much they can differ and why it’s important to shop around to get something you are happy with.  

(I have linked these products on amazon. If you end up buying one of them through my link below, I may get a commission from amazon at no extra cost to you, which helps support this website).

BioGold

NPK: 5.5 – 6.5 – 3.5

This is pretty much the most common fertiliser from Japan that is used in bonsai. As you can see it’s well balanced and not too high in any ingredient.

This is used by people with quite well developed bonsai trees as well as those still in training.

Bonsai Focus

 NPK: 1.9 – 0.7 – 3.9

This is a very popular “bonsai fertiliser” on Amazon. Of course it is potentially being bought by people who don’t know what they actually need, but as you can see it’s got quite low levels across the board, this would actually be okay with a well developed bonsai tree.

This would not be as good on something you are trying to develop and pump up.

Westlands Bonsai Feed

NPK: 1.8 – 1.0 – 2.3

Again, very popular on Amazon, potentially being bought blindly by people. But as you can see it is also quite low in its levels so this would be excellent for a bonsai tree in refinement.

Again, this would not be the best fertiliser for a tree you are trying to grow and thicken up.

Miracle Grow All Purpose

NPK: 24 – 8 – 16

This is absolute rocket fuel designed for driving crazy growth in the garden. It actually says on the box “grows plants twice as big” and I don’t doubt that.

This is going to be perfect for developing those young trees. However, you might want to keep it away from the more refined bonsai trees.  

Miracle Grow All Purpose Concentrate

NPK:  7 – 3 – 5

This is designed for plants in pots plants as well as in the ground, so it’s not as extreme as the full strength Miracle Grow and it’s a more rounded fertiliser.  This would be totally fine to use with most bonsais.

Westlands Bone Meal “Root Builder”

NPK:  3 – 9 – 0

This is commonly used by gardeners to enrich the soil for root growth and as you can see it does lean towards the Phosphorous (P) which will help with root growth.

This fertiliser even has zero Potassium (K). You will find others like this where they don’t even include certain nutrients. Having zero nitrogen is a common one that is used in bonsai to try and avoid excessive top growth, and instead focus on the roots.

As you can see form this snap shot of fertilisers there is quite a large range with what is available.

There is also nothing stopping you buying something like the super strong miracle grow and using it on your developing trees as the packet suggests, but then diluting it with twice as much water, to weaken it for your more developed trees. You could also fertiliser less often or use less than the recommend amount in the suggested water amount.

Although this isn’t quite accurate, it still is possible. However, I would be very careful going the other way. Don’t think you can add twice as much fertiliser and make it twice as strong or give them the recommended dose twice as often. This will probably be too powerful and damage your trees. Less fertiliser is always better than more.  

What Is The Best Fertiliser For Bonsai?

This isn’t a question I can answer. This comes down to you, your bonsai and its goals and current situation.

I currently use the full strength Mircale Grow rocket fuel. However I am still developing a lot of my trees. For the ones I don’t want to get too big, I either use less powder when I make a batch, or just I feed them less frequently compared to others.

What works for me, but might not work for you.  

Just remember that pot size, soil type, species, time of year your climate and how healthy your tree is and all sorts of other factors will all have an effect on how the fertiliser works. The amount I give my trees is enough, but for yours, it may be too strong.

If you are not sure what you are doing, just get a well rounded one and feed you tree as per the instructions. They are generally quite conservative and shouldn’t have any issues.

Just look at the very popular biogold as rough guide for what is classed as a good all rounder for bonsai. If you can find something like that, you should be able to keep your trees healthy enough until you gain some confidence with experimenting with things.

(You can read more about – When Do You Fertilise A Bonsai?)

Conclusion

There is nothing wrong with Bonsai fertilisers, but you need to be aware that are not always the best option for your bonsai.

Hopefully now you are able to start looking at what your goals are for your bonsai and work out what each fertiliser can offer you and then make you decision based off this.

(You can read more about – What Is The Growth Rate Of A Bonsai Tree?)