Fertilisers research and deep dive

Hello,

I am looking into fertilisers.
I grow my trees in akadama mixes (deciduous and evergreen).

I’ve started with liquid fertilisers from a local supermarket (NPK 4-3-9).	Attachment IMG_0175.jpeg not found
Next year, I have learned about slow release fertilisers, like Osmocote (NPK 15-9-11). I have used this and also the liquid fertiliser.	Attachment IMG_0176.jpeg not found
then organic slow release fertilisers, like Biogold (NPK 5.5–6.5–3.5) I have used this together with the liquid fertiliser.	Attachment IMG_0177.jpeg not found
Now, I came across beneficial bacteria cultures, like Danú. Has anyone tried something like this before? bonsai4me.com/store/Dried-Danú-Mainland-...d-Ireland-p392179589	Attachment IMG_0178.jpeg not found
I also came across this ‘beast’, called Peters, with an NPK of 20-20-20. Has anyone tried it? These numbers scare me!	Attachment IMG_0179.jpeg not found

Any info on Danú and Pieters is much appreciated!

Actually osmocote is not slow release fertilizer. It is control release fertilizer. Which means it release more when hot than cold and more when wet than dry.

I have am naturally suspicious to all kind of natural bacterias in cans. Bacterias is not that easy to make survive in dry, oxygen depleted materials. However, the bacterials that may benefit your tree will colonise your soil if the right conditions apply no matter if you add them or not.

High number of npk is normally not an issue. Just add less of the product. Just watch out for high levels of amonia that will burn roots if overused.

In bonsai I sometimes read that the products with same values for all NPK componds is called "balanced". But in fact they are not. According to a lot of studies (fex redfield et al), the natural balance between nitrogen and phosphorous is 16 to 1. A little lower may benefit flowering, but 1 to 1 as in "balanced" fertilizer will for sure waste a lot of phosphhorous.

I use Danu when repotting, superb. I use Biogold and seaweed extract as well. Works well for me

Tropfrog wrote:

Actually osmocote is not slow release fertilizer. It is control release fertilizer. Which means it release more when hot than cold and more when wet than dry.

I have am naturally suspicious to all kind of natural bacterias in cans. Bacterias is not that easy to make survive in dry, oxygen depleted materials. However, the bacterials that may benefit your tree will colonise your soil if the right conditions apply no matter if you add them or not.

High number of npk is normally not an issue. Just add less of the product. Just watch out for high levels of amonia that will burn roots if overused.

In bonsai I sometimes read that the products with same values for all NPK componds is called "balanced". But in fact they are not. According to a lot of studies (fex redfield et al), the natural balance between nitrogen and phosphorous is 16 to 1. A little lower may benefit flowering, but 1 to 1 as in "balanced" fertilizer will for sure waste a lot of phosphhorous.

Thank you for your correction: osmocote => control release fertiliser, and also for the term: balanced fertiliser.

You’ve mentioned studies on fertilisers. Can you share the outcome?

Do you prefer a certain type of fertiliser over another? Would you mix them up (e.g. slow release fertiliser with liquid fertiliser in the same growing season)?

m5eaygeoff wrote:

I use Danu when repotting, superb. I use Biogold and seaweed extract as well. Works well for me

Cool, I think I’ll give Danu a try next spring.
Do you use it on any time of tree? Nitrogen fixers, pines and deciduous?

Are Seaweed extracts soluble? Can you please share a link?

Seaweed extract is freely available, just search. Danu is added when re potting, the dry product is longer lasting and goes further.

Same place as Danu sells seaweed extract

Razvan wrote:

You’ve mentioned studies on fertilisers. Can you share the outcome?

Do you prefer a certain type of fertiliser over another? Would you mix them up (e.g. slow release fertiliser with liquid fertiliser in the same growing season)?

Actually I mentioned studies about about the natural balance between nitrogen and phosphorous, not studies about fertilizer. That started in the ocean with the redfield ratio (1934). It has been used as a reference on many other studies on primary producers. In some a slightly higher ratio has been proved better for production, in some a slightly lower. The so called balanced fertilizers (meaning n equals p, equals k). Has not yet proved to be better for any crop. But it is still mentioned by orchid and bonsai hobbyists. The studies I have seen is just on different crops. In bonsai we don't necessarily want as much growth as possible, we want short internodes and trunk thickening. As far as I know there are no peer reviwed studies on that.

I use my pond water for watering my trees. It has low levels of N and P as NO3 and PO4 in a perfect ratio (10 to 1 measured in that compounds). Very unregularly I add some liquid sea weed into the watering can. In the hight of the summer I add osmocote for a little extra push. That is what I have been doing since I started this hobby and has never thought about changing it.

This is a very interesting read on beneficial soil bacteria:
www.gardenmyths.com/beneficial-microorganisms/

Obviously peer reviwed articles on the benefits on bonsai is far inbetween. But I like the part in the article that mentions that organics need to be added to sustain the bacteria and that the organics itself contains enough to "seed" the soil with bacteria. In bonsai with 100% inorganic substrate the bacteria population would be less than with some organics added no matter if bacteria products is added or not. If a tree is in mainly inorganic soil and fertilized with mineral fertilizer the precense of bacteria would make no difference. The bacteria is there to convert organic bound non awailable nutritients to mineralized awailable nutrients. If the soil contains no organic bound nutritients and only mineralized fertilizer is added not much bacteria will grow and make absolutely no difference.

For the sake of it, I do not question that people have good experience in using it. There are no doubt about that. I just question that it makes any difference and the article support that.

Liquid fertilizer probably gives a big boost to the tree and then washes out with watering so the tree develops long twigs with long interludes. Solid provides small amounts over a long time, promoting short twigs and smaller leaves,

Fish oil would be an exception.