Peter Tea—Repotting
Content re-shared from Peter Tea, visit www.ptbonsai.com
The following are things we can do with our Bonsai in January and February
Repotting (Just about all trees, tropicals are typically repotted in the Summer)
Ground/Air Layer (mostly on deciduous)
Styling of Conifers
For any one tree, plan on doing only ONE of the above techniques this Winter season. More than one may be too stressful for the tree and cause a decline in health.
Key Concepts that affect the rate of growth in Bonsai:
Sun
Water
Soil and Container Size
Repotting Interval
Fertilizer
Cutting
Why Repot?
The reason we repot is to manipulate how the Bonsai grows. All techniques in Bonsai was developed to direct the growth of the tree so we can then turn them into Bonsai.
Here are some reasons as to why I would repot a tree.
The tree is in a mix that is too wet
The tree is in a mix that is too dry
The tree is so root bound that the health of the tree starts to decline
To slow the growth of a tree (trees that are too strong)
To accelerate the growth of a tree (trees that are weak)
To develop the root spread and root system
To get the tree into a mix that is manageable by the owner
To change the planting angle of the tree
To place in larger pot for tree health
Just like the other techniques we apply to our Bonsai, always consider the species and health of the tree and vary your degree of root pruning. As you’re repotting, you should also ask yourself these questions.
Did we continue the development of roots?
Did we get the tree in the ideal position?
Is the tree firmly tied to the pot?
Is the soil mix we’re using going to cause the tree to grow too fast or too slow?
Is there enough or too much room for the roots to grow?
Is this an appropriate pot for the tree?
When to Repot
The best time to repot in the bay area is December through February. Start with deciduous trees first then conifers. Once the trees have been repotted, make sure to protect them if there are sudden hard freezes during the Winter.
Repotting Interval
Deciduous
Developing: 2-3 years
Refinement: 1-2 years
Conifer
Developing: 2-3 years
Refinement: 3-5 years
Broadleaf Evergreen
Developing: 2-3 years
Refinement: 1-2 years
Repotting Early vs. Later
Due to our mild Winters, it can make a difference repotting in December vs February. It all comes down to how fast you want the Bonsai to grow. Repotting in December generally yields a strong Spring push whereas repotting in February slows down the Spring push. The difference is not huge but can be enough to affect how refined trees continue to develop.
[Peter’s] recommend soil mixture are as follow:
Deciduous: 50% Akadama, 25% Pumice, 25% Lava
Conifer: 40% Akadama, 30% Pumice, 30% Lava
Be sure to sift all your soil to size so that you have a medium and small size mix. Medium is used for larger trees and small soil for smaller trees. Also, make sure to bring medium size pumice by itself to be used as a drainage layer if needed for your trees.
Soil Mixtures Peter Tea Uses
Conifers:
Fast growth mix: 33% Akadama, 33% Pumice, 33% Lava
Average growth mix: 40% Akadama, 30% Pumice, 30% Lava
Slow growth mix: 50% Akadama, 25% Pumice, 25% Lava
Deciduous:
Fast growth mix: 33% Akadama, 33% Pumice, 33% Lava
Average growth mix: 50% Akadama, 25% Pumice, 25% Lava
Slow growth mix: 75 % Akadama, 12.5% Pumice, 12.5% Lava
Broadleaf Evergreens:
Can use either Conifer mix or Deciduous mix. Dependent on species of plant material.
Soil Sizes and Container Sizes
Soil sizes can change how much water it holds. Smaller soil has more surface area in a given container and surface tension of water plays a larger roll. Generally small trees uses smaller soil and larger trees uses medium size soil. When creating your soil mix, keep the sizes of the individual components as consistent as possible. Large particles have a tendency to work its way up towards the top and small soil tends to work it’s way down. Use a sifter to sift the soil to size and remove the dust.
The size of the container also plays a role in how much water is retained. Large containers have larger surface areas and tend to hold water longer. Very small containers don’t hold much water at all. Think about the size of the container, the soil mixture you’re planning on using and make the adjustments needed to get just the right amount of water retention.
Repotting Steps:
Raw trees:
Cut tie downs wires
Use a root sickle to cut the sides of the container
Remove the tree out of the container
Fine the root spread by raking the top soil
Lay the tree on its side and rake the bottom of the soil ball
Bring the tree upright and lightly rake the sides
Bare root if the tree allows it. If not, bare root a small section
Prepare the container with screen and tie down wire
Add drainage layer of soil if needed
Add small amount of Bonsai soil into container
Place tree on top of soil and slightly work the tree down into the soil
Make required adjustments in side to side lean, front to back lean, offset and soil level.
Add a small amount of Bonsai soil and work into roots
Tie root mass down with tie down wires
Add more soil and work into roots with chopstick. Keep filling soil to the desired level
Water the tree till the water runs out the bottom of the container. Keep water till the water runs out clear.