Can I use Physan 20 and Mycorrhizal Fungi together?

[sheadog]

I posted this question on the beginners forum and am not getting any responses, so I thought I would place it here.

I am going to be breaking open a flask and have never done this before. I feel confident in all steps; however, some info I have read says soak new roots in Physon 20 and others state that you should apply a mycorrhizal fungi root product for healthy new root growth. It seems to me that Physon 20 would kill the mycorrhizal fungi? Is there any suggestions? I want to be certain that the different orchid flasks that I crack in the future get the best start that I can give them.

Thanks,

[johnblagg]

Together...I would say No.
And in fact I would be very cautious of Physan on very tender new plants right out of flask ...or any other chemical for that matter even fertilizer to start with I would use lightly untill I had them adjusted to the change from flask to open air conditions...mycorrhizal fungi on the other hand I dont think would pose much danger.

[King_of_orchid_growing:)]

...

However...

The kinds of mycorrhizae commonly sold are not the ones that epiphytical orchids form a symbiosis with.

The mycorrhizae you'd want belong to the group collectively known as Rhizoctonia. Taxonomy for fungi is complicated. I suggest reading more about them.

[sheadog]

Thank you sooo much. I will apply the mycorrhizal fungi accordingly and leave the Physan 20 for my more mature orchids. Geeees, I love my orchids way tooooo much.

[gnathaniel]

Actually, sheadog, I would recommend you do the opposite. A short soak (really more of a thorough rinse) in a very weak solution of Physan 20 (I think the package has directions for recommended concentration) is often a really good idea when deflasking seedlings. There are all kinds of fungal spores in the air that can quickly colonize and kill your tender baby orchids. Putting a small amount of Physan in the soaking water for the compot medium also works well. Even with Physan you may get some fungal problems, so make sure you have a fan in the room/GH to keep up good airflow.

As Philip indicated, the mycorrhizal fungi you have are unlikely to be of a type that are beneficial to orchids. And even if they're the right kind, these fungi can still quickly overgrow and kill your seedlings, especially if the plants are coming out of sterile asymbiotic flasks. Just my , of course... Good luck!

--Nat

[Royal]

I'm with Nat. I use Physan in a spray bottle to help "pressure wash" all of the media from the roots of deflasked plants. I mix it weak, about 1/2 tsp per gallon - no problems.

The whole orchid/fungus symbiosis thing is still not fully understood. While it may be a huge part of the propagation of wild populations, in cultivation the nutrient media in a flask gives the plants everything (and more) than the fungus would supply in nature. Studies have also shown that looking at the same species, in the same area, that the type of fungi varied from population to population.