Soil mix

[Fungible]

Hello im new to caring for bonsai and want to grow bonsai from seed I just wanted to ask if having a soil mixture composing of lava rock, pummice, zeolit and sphagnum moss is good enough. Also what kind of material I should add.
Thanks a lot

 

[Wires_Guy_wires]

Yes, that's good enough but don't use too much sphagnum. Just some sprinkles.

 

[Shibui]

Your soil mix may depend what seeds you are trying to germinate.
A coarse mix with larger particles is not so good for very small seeds as they tend to wash down too deep in the pot. You may be able to get away with a layer of finer particles on top of the coarse mix.
Larger seeds will usually grow just fine in a coarse mix with largish particles provided it holds enough moisture or you can water often enough to avoid the germinating seedlings drying out at the critical time while the roots are first emerging'

Need to be aware that the stated mix has little or no nutrients. Your seedlings will need fertiliser soon after they germinate to get good growth.