On Apr 15, 8:21 pm, Jangchub wrote:
On Tue, 15 Apr 2008 14:50:45 -0700 (PDT), Father Haskell



wrote:
On Apr 15, 10:44 am, Jangchub wrote:
On Mon, 14 Apr 2008 22:33:28 -0700 (PDT), Frank
wrote:

50 / 50 vermiculite / perlite mix, no soil, no peat, no compost.
Excellent water handling characteristics, pH would remain dead
stable. No pests, no disease. Feed with organic tea to replace
the missing OM portion. Would this work as well as a good
standard potting mix such as Pro Mix?

The problem with this mixture is that there is too much air space and
plants will not develop roots the way they ought to. Generally, that
air space is filled with peat or coir and the moisture in that portion
of the mix is what supplies feeder roots or root hairs with capillary
water.

Coarse sand? Shredded newspaper?

Why do you want to use this mixture?

Trying to do without peat for various reasons. Paghat
has a good article on her page that explains why. pH
maintenance is an escalating battle once the stuff starts
breaking down, which kills off everything for mysterious
reasons. Coir would be a great substitute, but it's too
hard to find in the Baltimore area.

Meanwhile, the tea I've been brewing works beautifully.
I'm wondering if I can't use it in full place of the solid
OM portion, eliminating a source of many headaches.

When I was a professional greenhouse grower we used peat pro mix on
very expensive and rare asexual plants which were being raised for
market. It sometimes took ten years for plants to become stable
enough to name them and market out.

How much lime did you add?

Never in the years I did this did we ever come across an escalating
battle once the stuff started breaking down. We did have to maintain
close records of our soils for operation permits and such, but I'm not
sure I ever heard of the claim that peat is killing everything for
mysterious reasons.

pH drops, so does uptake of nutrients such as Mg. Plant
"mysteriously" turns yellow with brown spots. "Mystery"
is solved when indicators (Rapitest pH test, Bromthymol
blue) and meter all show 5.0 pH. Plants recover quickly
and start to thrive with one application of hydrated lime
(1 tsp / gallon). Nice if I didn't have to keep doing that.

Do your research. Because it is on the Internet
doesn't mean its accurate, my own post included.

My research. My claim, not Paghat's.

I don't like the use of peat because it is depleting the peat bogs at
rapid rates and these bogs do not recover easily.

Bingo. My biggest complaint, too.