On 10/07/2013 17:30, Emery Davis wrote:
I flipped through last night to his garden makeover show, can't remember
what it's called, just as he was plunking a large tree into the ground,
which happily turned out to be a Gleditsia and not a Robinia, many of
which are dying miserably around here now, a large one near us that had
been resisting is currently nearly leafless.

He did a decent job planting, though I've never actually used one of
those watering gizmos, and people I respect hold that it's a bad idea to
have the tree circled forever with a whopping plastic tube.

But, then he wafted a little bit of mycorrhizae into the hole, and gave a
not great explanation of what it does (they are symbiotic with the roots,
providing elements and moisture in exchange for food, as I understand it
and simplifying, which of course AT was doing to).

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 had a look at the spreadsheet at Rootgrow's website and saw how much
they recommended.

But one of their FAQs is "What happens if I over or under dose?". The
reply is:

"The rootgrow application rates have been carefully worked out to make
rootgrow as economic and reliable as possible. If you overdose you will
simply waste money and confer no additional benefit to the plant. If you
under-dose colonisation will be slower maybe 1-2 months rather than 2-4
weeks."

If that is accurate (and they don't seem certain as to what the
timescale really is!), why not save money by underdosing? Would 2 - 4
weeks make a real difference? Seems to me you could experiment with
varying the dose with a few identical seedlings to see if there really
is any difference after a couple of months.

--

Jeff