Any thoughts or experiences with using Trichoderma harzianum in the soil?

[Mrs.Green]

I came across an add for this microbe , here in Norway. Since I have often thought about what we are really offering our plants to grow in ( or rather the likely lack of several beneficial komponents) I found the add interesting. Googling a bit I came up with several hits but this warnings about how to handle it, was a bit off putting, if this isn’t a case of ‘CAUTION: the coffee is hot!’ on plastic coffee mugs?

https://www.koppertus.com/content/usa/p ... e_20kg.pdf


https://gardenerspath.com/how-to/organic/trichoderma/

[DaveW]

I have used the fungi that supposedly grow on the roots, but I did not notice much effect. Maybe they were really the ones for "normal" plants rather than specialist ones for cacti?

https://www.rhs.org.uk/advice/profile?pid=633

That fungus sounds a bit nasty though.

https://www.mold-advisor.com/trichoderm ... 0of%20Mold

I knew a lady who went away to Spain for a few months and when she returned found her car seats had got a bit mouldy. She cleaned them off without any form of face covering and had breathing difficulties for a month or so afterwards. Therefore you need to take precautions and avoid breathing them in.

If your plants are growing OK I would avoid it personally.

[One Windowsill]

There was a case of someone dying from turning an old compost heap that had not been touched for a long time. Fungal spores are best avoided, especially breathing them. Luckily I seem to have a lot of spare masks around now.

I think some cacti have associations with bacteria in their natural setting.

[One Windowsill]

Rock-eating, phosphorus dissolving, trace element-releasing, nitrogen-fixing bacteria carried on the cactus seed.

Many papers:
https://scholar.google.co.uk/scholar?hl ... osis&btnG=

"the seedlings grow in pulverized rock for at least a year without fertilization and without showing distress"
https://www.fs.fed.us/pnw/pubs/journals ... nte001.pdf

[Mrs.Green]

Thank you DaveW and One Windowsill for interesring links I assume that there could be symbiotic ‘relationships’ between some ( or maybe many?) cacti and fungi/bacteria. But I would also assume that symbiosis between cactus species NN and fungi or bacteria would require a specific species of bacteria or fungi, so you can’t simply add any of the two and hope for a result. On top of that I would belive that the bacteria/fungi may not like the offered conditions in a flowerpot were the substrate may be wrong/missing elements needed. I don’t think drowning the plant/soil in a variety of pesticides would help either?

It’s very interesting though and I suspect we are only merely scratching the surface when it comes to our knowledge about nature.

[One Windowsill]

I don't know if plants in cultivation have retained those bacteria. They are very specific strains, which is why the plants carry them over from one generation to the next. Artificial feeding might lead to them dying off.

I would be fascinated to know if anyone has been successful growing cacti in nothing but crushed rock and with nothing but water.

[Steve Johnson]

I don't know if plants in cultivation have retained those bacteria. They are very specific strains, which is why the plants carry them over from one generation to the next. Artificial feeding might lead to them dying off.

I would be fascinated to know if anyone has been successful growing cacti in nothing but crushed rock and with nothing but water.

Crushed rock and nothing but water -- that experiment has been tried before, and it fails every single time...

What you just described is taking an essentially hydroponic approach, which is what I do growing the vast majority of my cacti in a pumice and granite gravel mix. I'm not the only one growing cacti in a soil-less mineral mix, and as it is with growing plants of all other kinds hydroponically, they need to be fertilized pretty much every time they're watered. If we don't do that, we'll eventually end up with dead cacti.

Given my limited knowledge on the subject, my understanding is that bacteria beneficial to nutrient uptake of cactus roots are present only in their native soils. Take a potful of that soil, and we'll find out that once it gets saturated, it takes forever to dry out. Mycorrhizal fungi are a good alternative to chemical fertilizers for non-xeric plants, but I don't know if that would work for container-grown desert cacti. Certainly not with soil-less mixes.

I realize that "chemical" is a dirty word with people who operate by emotion rather than reason, but there's nothing wrong about using chemical fertilizers for cacti as long as they're properly understood and applied. There may be beneficial strains of bacteria that support the different mixes growers use, although we'll need to see the evidence before we think about viable alternatives to chemical ferts.

[One Windowsill]

In the paper I linked above the substrate used in the experiment was decidely porous and well drained:

Ancient extrusive igneous rocks (lava flows) were subjected
to bacterial weathering experiments after being oven-sterilized
(250°C, overnight), pulverized in a mill, and sieved to obtain <90-
um particles (rock flour). Rock flour (4g) was mixed with 23g
pulverized perlite and placed in small black pots.