Tips For Repotting Your Bonsai

Any plant that grows in a container will eventually need to be repotted. Sometimes this is because the plant in question outgrows its current living space, like a hermit crab that needs a new shell. And other times, it is simply because the plant has reaped everything it can from the soil and needs a fresh start.

In today’s blog, we’re going to be offering some insight into the repotting process. The first time you repot your bonsai can be scary (or the tenth time if it’s a beautiful and mature tree that you’ve been putting your blood, sweat, and tears into for twenty years). Like anything else in life, repotting takes practice, but with a little patience and the right tools, you can successfully transfer your bonsai into fresh soil and watch as it thrives.

How Often Should I Repot My Bonsai?

This is one of the most common fears that bonsai owners experience when repotting. Does my plant need to be repotted? What happens if I repot it too soon? Based on the age and the species of your tree, you might need to repot it anywhere from every one to five years. Young trees or fast-growing trees will need to be repotted more frequently than mature trees. Your tree will let you know when it is time to repot with one major indicator: the roots.

To examine the roots, gently lift the entire tree out of the pot by grabbing the base and wiggling it loose. If you pull the tree out and see a twisted mass of roots, it is time to repot. If you still see a good amount of soil, you can likely wait another year and check again.

For an earthbound tree, the roots will continue to grow out or down for the life of the tree. However, for a container-bound tree, the roots will still grow but they will have nowhere to go. This is frequently referred to as ‘rootbound,’ when the roots begin to grow around each other and choke each other out.

What Time Of Year Should I Repot My Bonsai?

Deciding what time of year to repot is incredibly important to prevent trauma to the tree. Most bonsai trees will need to be repotted in early spring. This is because the tree is still dormant and can dedicate its energy to regrowing its root system rather than maintaining its leaves and flowers. Plus, when spring comes and the tree enters into another growing phase, the quick growth will help the tree recover from the transition. Just be careful to not repot too far before the growing season, as this can leave the roots unhealed for too long, exposing the plant to disease.

Can I Keep Using The Same Pot?

‘Repotting’ might be a confusing, and occasionally incorrect, term. Typically, repotting means to take a plant out of one pot and put it into another, but this isn’t always true of repotting bonsai. The most important thing to remember about repotting is that it is more about giving the plant new soil than a new pot. However, if you feel like your bonsai has outgrown its current home, upgrading to a larger pot is helpful, but not always necessary.

Choosing The Right Bonsai Soil Mixture

Before you begin the repotting process, you will want to create your bonsai soil mix. There are three qualities you want from your bonsai soil: water retention, drainage, and aeration. If one of these is missing, you can end up with an unhealthy plant. Water retention helps ensure the roots have time to soak up the water they need from the mixture, while drainage ensures the excess water can drain away as to avoid root rot. Finally, aeration is essential for the roots to receive oxygen, as well as for them to find loose pockets where they can easily grow.

The most basic bonsai mix will contain two parts akadama, one part lava rock or pumice, and one part organic compost (such as peat moss or pine bark). However, some bonsai growers do not use any organic material in their bonsai mix. This is largely up to personal preference and how your tree responds to different environments. At the end of the day, as long as your soil mix has good water retention, drainage, and aeration, and you use a bonsai fertilizer for nutrients, you are on the right track. Finding the right mix may take some trial and error, but consulting your local experts can certainly help. If you are looking for a mix that the experts use, try our special bonsai soil mixture developed by our very own Clark Long!

It’s Time To Repot!

When you have your potting mix ready, you are ready to repot. We’ve listed a step-by-step guide below for what the repotting process can look like.*

  1. Remove the tree from the pot and rake out the excess soil from the roots. You can use a bonsai root rake or a simple kitchen fork will do the trick. Use the rake and a shaking motion to remove a good portion of the old soil from the root ball.
  2. If the roots have formed into a thick mass, gently untangle them as much as possible.
  3. Using sharp scissors, prune back some of the longer roots, roots that look weak or dead. As long as you do not remove more than a quarter of the overall roots, the tree should be able to bounce back and repair itself in its new pot.
  4. Next, prepare the new pot (or rinse out the old pot if the bonsai is returning to its old home). Use bonsai wire to secure mesh over the drainage holes, which will allow the plant to drain without losing the potting medium. You can also feed this wire up into the pot and use it to secure the bonsai if needed.
  5. After your pot is ready and your tree has been pruned, put the tree into the pot and fill around the tree with your potting mix. Do not pack it down too firmly, as this can create a lack of aeration. The soil will naturally settle between the roots, and you can add more over the next few days if soil levels look low.
  6. After you have repotted your plant, add an organic bonsai fertilizer and thoroughly water it. Continue to monitor its health over the following weeks.

*Keep in mind, these are general repotting instructions. If you have a lot of stake in your bonsai plant and have concerns about your ability to successfully repot it, be sure to consult a local bonsai expert who can assist you in repotting your tree and advise you on the proper soil mixture for bonsais like yours.

Give Your Bonsai The Best Soil And Fertilizer

Here at Clark M Long Biogold Original, we specialize in providing bonsai enthusiasts everywhere with the materials they need to help their bonsai thrive. When it comes to repotting time, choosing the right bonsai soil mixture and following up with an organic fertilizer can make the transition easier for your tree. Shop our collection of fertilizers and soil amendments today, and feel free to reach out to us if you have any questions about your bonsai or our products.