Garden fertilizer with inorganic soil mix

Hello to everyone.

This is my first post on this forum. I have a probably basic question:

Can I use universal organic pelletized garden fertilizer (not specific for bonsai) with inorganic soils like lava, pumice etc…? I tested it with normal organic soil in pots and it works great. On the package it is written that in the garden one fertilizing will be enough for a season. I know that in the pots it is necessary to fertilize more often.

I have mostly small plants in development stage that I recently repotted in to inorganic soil mix.

Thank you in advance for the replay,


1 Like

It should work very well. I have used an organic lawn fertilizer as the main constituent of my fertilizer scheme for several years. The primary downsides are: 1) they are often higher in nitrogen (N) than optimal and 2) they are often closer to granules than pellets. The first can be addressed by adding organic components to add phosphorous (P2O5), potassium (K2O) , and other trace elements (yours is 7-7-7 which is a reasonable balance). The second will lead to a crust on the soil surface that needs to be removed or you can pelletize your mix. I mix up my organic components with a liquid fish fertilizer to make a thick paste that I then extrude using a sausage extruder to make my basic pellets. However, I am using some of the commercial pellets on my nicer trees since I got some at a decent price last year.

1 Like

Hello Jacek,

welcome to the forum. As MartyWeiser already put down, there is nothing wrong with your fertiliser for use in Bonsai. Many will use additional supplements (like the mentioned fish emulsion/hydrolysate, kelp products, Humic acids etc.). If you have smaller plants in development one could argue if this is really needed.


I had no idea that I can make custom fertilizer pellets at home. In that case I will use it and from time to time add biohumus, seaweed or fish emulsion.

1 Like