Growing a bonsai from a seed is less complicated than many hobby gardeners think. The advantage is that you can shape the bonsai tree according to your own ideas right from the start.
Table of Contents
Seed selection
There are no specific species for bonsai, they are grown from the seeds of normal-sized trees. Those who prefer native species can, for example, get spruce, fir or oak seeds from the forest. The removal of young plants from the forest is not recommended and even forbidden in some regions.
The forest floor is rich in nutrients, which is why young trees there already grow strongly in the first few months. In comparison, the special soil for bonsai also contains nutrients, but to a much lesser extent. This gives them a squat growth right from the start. In addition, the light conditions in the forest also force height growth, which is also unfavorable for the cultivation of bonsai.
If you want to grow more exotic species than bonsai, you can collect seeds in parks, for example, because non-native trees are occasionally planted there. Alternatively, you can also ask in botanical gardens, for example, whether they can get some seeds from special trees.
sowing time
Sowing time can vary from species to species. Native seeds that you can use for a bonsai often need a cool period to germinate. This phase is called stratification and is an important factor for the seed to germinate in the first place. In the case of native species, it is therefore often better if they are sown in autumn and left outdoors over the winter. If this is not possible, you should simulate stratification. To do this, place the sown bonsai seeds in the refrigerator for one to two weeks.
Selection of species that require a chilling period:
Exotic tree species can theoretically be cultivated all year round, as they usually need room temperature to germinate. However, the young trees need sufficient light in the first few months. It is therefore possible that you will also need a suitable plant lamp for late sowing, otherwise the trees will grow too quickly in search of sufficient light.
Substrate
To germinate a bonsai should get a suitable substrate for this culture. A distinction is made as to whether it is a coniferous tree or a deciduous tree. Coniferous trees usually require a substrate that is slightly more nutritious than deciduous trees.
Special substrates for the plants are occasionally even without humus soil. However, this is associated with a higher maintenance effort. Akadama is used instead. A special dried clay granulate to which different rocks such as pumice, lava granulate and fine gravel or sand are added. With bonsai trees, aeration of the soil in the pot plays a major role. You can replace Akadama proportionately with humus soil or potting soil, which will make the trees grow a little faster, but the soil will not be as well aerated.
Mixture for conifers:
- 30% Akadama each
- 30% Bimskies
- 30% Lavagranulat
- 10% Humuserde
Mixture for deciduous trees:
- 40% Akadama
- 25% Bimskies
- 25% Lavagranulat
- 10% Humuserde
sowing
Before you plant the seed, it is important to know whether the tree species is a light germinator or a dark germinator . Light germinators need light to germinate, while dark germinators must be covered with a layer of soil.
The rule of thumb for most plants is that the smaller the seed, the closer it needs to be to the surface. Flat and small seeds are therefore mostly light germinators. These include, for example, spruce or fir. Seeds of walnuts or oaks, on the other hand, are very large and should be covered at least as much as the seed grain when planted. Occasionally, dark germs also germinate on the surface, which is particularly the case with oaks. If a dark germ germinates on the surface, there is a higher risk that the seedling will die, for example because it cannot root well or does not get enough moisture.
Sow bonsai seeds:
- Fill the seed tray with substrate
- Distribute seeds with sufficient distance to each other
- Press light germs on and cover dark germs with substrate the same size as seeds
- pour on
Use an indoor greenhouse for cultivation, even if it is a question of frost germs that have to be outdoors over the winter. The indoor greenhouse has the advantage that it retains moisture better, which reduces the risk of the sensitive seedlings drying out.
maintenance
Until the seed has germinated, it is important that you keep the soil constantly moist. You should also air the greenhouse regularly to prevent mold from forming.
In order for the plants to develop well, it is important to transplant them after successful germination. In deciduous trees, this happens as soon as the first real pair of leaves has formed. For deciduous trees, the bonsai should be at least the length of a finger. When transplanting, you can already carry out a root treatment. You can shorten very long roots and remove dried or muddy root parts. Always make sure that sufficiently fine hairy roots remain on the young trees.
Instructions for repotting:
- Fill the bonsai pot with substrate
- Carefully lift young trees out of the ground with a pricking stick or a fork
- Press a hollow into the substrate along the length of the roots
- Plant young tree
- Press the substrate carefully
- pour soil
In the first week or two, until the bonsai has rooted, the substrate must be constantly moist. You can also put a transparent freezer bag over the pot and secure it with a rubber band, which will reduce evaporation. Air the bag regularly to prevent mold growth, just like when growing.
After about two weeks, the young trees should be rooted in the pot. Then you can remove the bag again. Choose a bright location for the young trees so that the growth remains compact after transplanting.
