On Thu, 11 Jul 2013 09:49:00 +0100, nmm1 wrote:

In article ,
Chris Hogg wrote:
On Wed, 10 Jul 2013 18:21:30 +0100, "Bob Hobden"
wrote:
"Emery Davis" wrote

The thing about mycorrhizae is that you need a pretty great whopping
lot of it for a tree that size, and the stuff is expensive.

I'm surprised at that. Never used the stuff, but I would have thought
that being a fungus, provided the soil conditions were favourable and
not hostile to it, the fungi would increase and multiply once the soil
had been inoculated by even a fairly small amount. After all, it's not
like a fertiliser, that slowly diminishes with time as it's used up or
leached out. The Rootgrow FAQ says "If you under-dose colonisation will
be slower maybe 1-2 months rather than 2-4 weeks", which makes sense.
Perhaps AT was aiming for long-term soil improvement rather than instant
effect.

You are right. From the Web site, it's hard to tell where on the snake
oil to miracle compound spectrum that is. They do say that mycorrhizal
fungi are host-specific, but don't give much of a clue as to which
plants would benefit, and their implication is that their mixture is
suitable for most plants. That sticks in my gullet from what I know
about mycorrhizal fungi. Also, some mycorrhizal fungi can be pathogenic
under some circumstances!

You want the fungus to be all around the roots, not just a little on one
side, which is what AT did. I don't know how long it would take to
propagate to the other side, but it could be a long time.

There is a lot of literature available with simple search of google
scholar, so if you're interested looking further than the Rootgrow web
site is probably a good idea. Rootgrow is, perhaps understandably, in
the business of selling a product, so caveat emptor applies accordingly.
It's certainly correct that not all treatments are appropriate for all
plants, which have broader or narrower specific symbioses; but of course
the Rootgrow people will be happier if they sell more, regardless of
whether your plants do better.

I'm all for AT telling the public about a product that, until quite
recently, has been difficult to obtain in consumer appropriate
quantities. But based on my experience he applied the product incorrectly.

-E
--
Gardening in Lower Normandy