Well, for one thing, I don’t use a “jet” of water to clean roots when bare rooting. A soft spray, yes, but not a jet. The mychorazzae spores are in the air. If conditions are favorable, it will grow. It actually prefers dryer conditions. So, when we see root rot, or root balls that comprise a high percentage of organics, we don’t see much mychorazzae because it’s just too wet.
If you are repotting a healthy tree, and want to make sure you keep a good population of mychorrazae going, it does no harm to this s tablespoon of the old soil back in the pot.
That said, when I’ve been potting trees at Boon’s, I’ve been there for hundreds of repotting. Never, not once have we ever “inoculated” a pot with any kind of mychorrazae! It just happens on its own.
It has to do more of having a suitable soil mixture, and following good watering practices.
Let me add thatwe generally don’t completely bare root conifers unless it’s an emergency. Usually, we bare root half the root ball one year, then the next year follow up and do the other side. Most of the time,once a tree is growing in good soil, no barerooting at all is performed
Here is a root ball I just started to work:
View attachment 188843
The lower half had been bare rooted the year before, into Boon Mix, and was full of white mychorrazae. The dark upper hhslf was the original soil from the nursery. Mostly pinebark and sand. Very little mychorrazae present! That’s because the pinebark and sand mix just holds too much water!
I had just started working the bottom of the rootball when I noticed the striking difference between to two halves.
No mychorazza was ever added to this tree.