Fungi can attack different parts of trees. They also cause damage to bonsai and attack roots, shoots or leaves. Their spores are airborne and often persist in the soil until growing conditions are favorable.
A permeable substrate prevents root rot
root rot
The roots need a well loose substrate in which sufficient aeration is guaranteed. It must be able to store water and nutrients without tending towards waterlogging or compaction. The right substrate mixture is the basis for healthy growth.
If the composition is not correct, the growth conditions deteriorate with each watering. As a result, the fine roots die off and become mushy. They offer an optimal breeding ground for fungal spores, which are naturally found in the soil. The hobby gardener usually notices signs when the root rot has progressed. It shows up as brown to black leaf spots.
Factors that favor fungal infestation:
- excessive supply of fertilizers
- heavy watering with the risk of waterlogging
- compacted substrate due to incorrect composition
mix substrate
Every bonsai has its own requirements for the plant substrate. With a self-made universal mixture, you create good starting conditions for healthy growth for most trees and shrubs. Mix together a part each of land soil, mineral substrate, and coco coir. Depending on the needs of the plant, you can vary the proportions or add hummus.
Pour right
As soon as the substrate surface has dried, first gently moisten the soil with a shower. When the water has drained away, water vigorously until it drips from the drainage holes. With this method you ensure that the entire soil is soaked. Dipping the bowl in a water bath is recommended in emergencies when the soil is extremely dry and compacted so that the irrigation water rolls off the surface.
White coating on the substrate
A permanently damp surface provides a breeding ground for mold, which manifests itself as a white lawn. Since this can have a negative effect on plant growth, you should replace the soil and plant the mini tree in fresh substrate. Clean the bowl with hot water.
tips
Not every soil fungus is dangerous. Special mycorrhizal fungi enter into a symbiosis with trees and provide them with additional nutrients.
mold growth on leaves
Powdery mildew is expressed by a mealy coating on the leaves. Its fungal mycelium penetrates the plant tissue so that it dies off in the event of a heavy infestation. Older trees usually survive a disease without any problems. It is sufficient if you remove the affected leaves and pay attention to optimal site conditions.
Young trees suffer more because they first have to develop a strong crown. A rapid spread of the fungus lawn can lead to complete defoliation and spread to the soft shoots. Treatment with sulfur-based fungicides is the last resort to destroy the fungus.