How To Go From A Large Pot To A Small Bonsai Pot

When you are developing your own bonsai you may have put your tree in a large pot, or even just bought it like that as nursery material. Large pots are fine; they serve their purpose, but ideally you want your tree in a smaller pot and trying to make this happen can be challenging at times.

I will go through some of considerations and techniques to make this happen, which are going to involve managing the top growth properly as well as working the roots over a couple of years to make them as compact as possible so that they can go into a smaller pot.

It Will Take Time To Reduce The Size Of Your Pot

Before you even consider the whole process of trying to get your tree into a smaller pot, you need to realise that this may take some time, and by that I mean a few years.

Throughout the whole process you need to make sure that the tree stays healthy, which is why it can’t be rushed. You will probably have to reduce the pot size over a couple of growing seasons, gradually getting smaller until you get to where you want to be.

You also need to realise that you can only do so much. We can reduce our trees root ball quite a lot, but there will be a limit to what can be achieved.   

How Quickly You Can Reduce The Pot Size Will Depend On The Species

One of the main things to take into consideration when reducing the pot size is the species of the tree you are working with.

Some species are going to tolerate a lot more root work than others and they will also respond differently too. This can make a huge different in both how long it will take you to reduce the pot size, as well as the final size you can actually achieve.

In general, coniferous trees like pines and junipers can be quite sensitive to root work and will be more difficult to work with compared to deciduous trees. This doesn’t mean you can’t get them into smaller pots, it just means it will take more work.  

It Will Also Depend On The Individual Tree

While the species is important, so is the individual tree. You need to look at what is in front of you and see what you are dealing with.

The history of the tree is going to affect how much work will need to be done and what can be achieved. A tree that has been growing unchecked in the ground for 20 years before going into a large pot is going to need a lot more work than a tree that has been grown from seed for 20 years in good bonsai soil, where its roots have been worked on a few times before.

Basically what I’m saying is … every tree has a different starting place, so the journey into a smaller pot isn’t going to be exactly the same for every tree.

The points I mention below are more of a general overview that you will have to adapt to your individual tree. Some trees you may need to take more time and reduce things more slowly, while others, you may be able to actually make it happen a lot quicker. 

Always remember to keep the trees health in mind and only go as far as is safe with your root work. If you do this, you will get there eventually.

Managing The Top Growth Is Important To Get A Tree Into A Smaller Pot

If you want to get your tree into a smaller pot, then the management of the top growth is important. Usually whatever is going on above ground is reflected below. This means if you have crazy long branches, you will also usually have crazy long roots.

If we look at it from a logical view point you will see why this is a problem, if you have a tree that is 8 foot tall and covered in leaves …it is going to need a lot of roots to support this. If you tried to cut all the roots off and place it in a small pot, then the roots are really going to struggle to meet the water demands of a tree that is this large.

This means that first step to getting your tree into a smaller pot is to start managing the top growth and you are probably going to have to start by cutting it back and moving into trying to ramify your tree.

If your tree is in a large pot, then you have probably been trying to develop it. Hopefully your trunk is the size you want and you have also got some good initial branches developed too. Now you need to stop letting the tree grow out and start focusing on reducing the top growth.

This will make sure that when you reduce the roots, they can still support the tree, basically you want the top and bottom to be balanced, which is going to keep everything healthy and happy.       

Develop Fine Roots

To get a bonsai tree into a small pot, you need a small root ball, which means you need a lot of fine dense roots.

If trees are left on their own, they will grow large roots, with small fine feeder roots at the tips. This is fine in nature, but not for bonsai and we will need to work on the roots to encourage the tree to only grow the fine roots. You do this by using a combination of good soil and pruning the roots.

Once you have a tree with lots of fine feeder roots, it will be both very healthy and also able to fit into a smaller pot.  

(You can read more about – What Do Healthy Bonsai Roots Look Like?)

Always Use Good Bonsai Soil

The first step to getting finer roots is to use good bonsai soil.

Bonsai soil helps cause finer roots as it is full of little gaps that can hold the oxygen and water the tree needs. It doesn’t need to send long roots out to find what it needs …its right there for it. The soil also dries out a lot faster, which sounds bad, but the constant drying and soaking of the soil actually causes the tree to grow more finer roots in that area.

The soil we use can also encourage the roots to split and divide, due to the sharp edges and small gaps the roots will often get small cuts, where more roots grow from. (Kind of in the same way how more branches will grow if you prune them)    

This all adds up to a tree that will have a lot fine dense roots. It is really incredible the difference you can see in the roots from just changing the soil from something like nursery soil to bonsai soil.

The sooner you get your tree into good soil, the sooner you can start reducing the roots ball.

Repot Your Tree More Often

The next way to encourage finer roots is to repot more often. Roots will just keep growing and the longer your leave them, the longer and thicker they get.

As I mentioned above, the sharp soil can cause the roots to get slightly damaged and divide into more roots … and you can do this too, through pruning.

Every time you prune a root it will divide into more roots and these will also get shorter and thinner each time too, exactly like the new growth that comes after pruning the branches.

This can take a few years to develop, but basically the more work you do on your roots, the better they get and over time you will end up with a compact root ball that can support the tree.   

You always need to think about the trees health, so you need to be cautious with your pruning and this is exactly why it might take a few years to get everything under control. Just take your time and do what you can without killing the tree.

Get Rid Of Large Support Roots

You will often find that trees growing in large pots have large, useless roots, which is the complete opposite of the small fine roots we need. 

When a tree is given space it will stretch out and this grow a lot of anchoring roots. You will usually find large thick roots growing in your larger pots. This will also happen in you are using poor soil. This is also why trees taken from the ground have large roots, they usually have a combination of a lot of space, and poor soil.

Usually when you remove a tree from the ground you have to cut some of these large roots back to fit the tree into the pot, even if it is going into a large pot. These roots are so big that they don’t even look like roots; they are just large sections of tree that hopefully have some fine roots coming off them. However, these sections usually end up dying back, so you may end up with basically just lumps of deadwood in the root ball.

This can be very common with air layered trees. The section of trunk that is below the new roots will die back, and now you just have a lump of deadwood sat under the tree.

These large roots and dead sections are just a waste of space, they add no value to the tree and more importantly take up space in the pot …if you want to use a small pot then space is pretty limited so the last thing you need is useless junk like this taking up all the room.

Removing these roots from the tree is going to free up some space and often will allow you to place the tree in a smaller pot, or at the very least it just makes more room for some actual beneficial roots to grow.   

Uncover The Nebari

When you have a tree in a large pot it is very likely that some of the trunk is going to be buried. This is extremely common with nursery trees. They always seem to plant the tree quite deep in the pot and basically burry some of the trunk.

This isn’t ideal for bonsai, as we like to see the nebari (or “root spread”). This is basically the bottom of the trunk, where it meets with the roots. If you look at a developed bonsai tree its trunk will start to flare out near the base and the trunk will transition nicely into the roots, and then the roots spread out into the soil. This can look awesome and it is a feature we want to display and enjoy, so having it buried under 3 inches of soil isn’t great.

However, uncovering this actually does more than giving us something to look at. If your trunk is buried under 3 inches of soil, simply removing this allows you to reduce the root ball by 3 inches …so now you can start to fit the tree into a small pot.

Really a lot of this soil is a waste of space. There are no roots growing here, so we really don’t need it and it is a very easy to reduce the root ball instantly, without actually having to do anything to the roots.

(You can read more about – Developing A Nebari (Spreading Roots))

Everything Together Will Reduce The Root Ball

If you just do everything I mentioned above and repeat it over a number of years, the root ball will reduce and each time you repot you can get the tree into a smaller pot. Of course there is a limit to how small you can go, but you will still be able to see a significant difference.

Don’t be frustrated if you can’t do everything at once, just keep chipping away at it and you will get things to reduce and you will be able to use smaller pots.

Also, always remember to put the trees health first, so long as you do that you will develop a great root spread that will fit into a smaller bonsai pot.