The best and fastest way to kill your Camellia sinensis tea plants is to use a potting soil that is formulated for bedding plants or vegetables. The reason for this is that Camellia sinensis root systems like a soil that gives the roots a chance to breathe. They will not tolerate soils that are compact with no air space. This is common with bedding plant soils.
Peat moss is a powdery fine substance that when wet, holds water near the roots. There are no avenues for the water to travel away from the plant roots. When you take a powdery fine substance, and add larger organic matter to it, water can get to the roots, but the larger pieces create voids in the soil structure where oxygen can be increased.
Tsubaki Tea Soil
We use a mixture of three different materials when we make our soil. We use a very fine, ground aged pine bark. The pieces are about 1/4 inch. We add larger pieces of bark to the smaller mix. The larger pieces are 3/4 to 1″. Then we add peat moss. A little is good, a lot is not.
You can often find these ingredients in a garden center especially if there is a tree industry, such as pines. You could also visit a local growing nursery that makes their own bark-based soil mixes for shrubs or trees.
Use this soil mix for any containers. Put rocks or other material in the bottom to keep the drain holes from clogging. This mix is excellent for amending your garden soil.
Our Soil Recipe
1 gallon Soil Conditioner/Mulch (Finely ground bark less than 1/8” pieces)
1 gallon Mini Nuggets (Small bark pieces 1” or less)
1 Cup Peat moss (ground)
2 Tablespoons Dolomite Lime
Alternatives to making your own soil:
You could use a bark based potting soil with a small amount of peat. Usually recommended for shrubs and trees. Sometimes labeled as Garden soil. Examine the ingredients.