Water retained by various soil ingredients

Nhu Nguyen xerantheum@gmail.com
Tue, 23 Oct 2012 18:23:07 PDT
Hi Mike,

Thanks for that interesting experiment. It's good to see numbers.

However, I have to say that I have pretty good luck with perlite. I use it
for everything except for Amaryllidaceae, sensu stricto. Allium and
Tulbaghia grow fine in perlite.

My typical mix for perlite is 50-60% perlite, 40-50% super soil. The
Hyacinthaceae loves it, and so does many other plants. For amaryllids, I
use a pumice mix, it's on the order of 50-75% pumice, 50-25% super soil.

With these mixes, I have not gotten any rot in the bulbs*, even with the
sometimes lengthy winter rain here. The only differences I can see that
seem to matter is the peat and pots. I use Anderson Bands available from
Stuewe and Sons. These bands have practically opened bottoms, so I use
fiberglass window netting to keep the soil in. I set the pots on plastic
racks that don't collect water. The result is a basically opened bottom
container that doesn't hold any water.

I avoid using peat for several reasons, but mostly because it decays very
quickly, leaving a very goopy mess that is sure to be bad for bulbs. It is
also high in pH, and probably needs to be amended.

*I have to note that I've been growing Calochortus in this mix and the
results have been disappointing. Some bulbs do rot out in my wet winter.
This year I'm switching to pumice and I think the result will be much


On Sat, Oct 20, 2012 at 9:56 PM, Michael Mace <michaelcmace@gmail.com>wrote:

> It's planting time in California, so I am once again playing around with
> soil mixes to see if I can find the ideal formula for my potted bulbs.
> Sand                                      1
> Pumice                                 1.4
> Redwood compost*             1.95
> Supersoil**                           2.2
> Peat moss                           2.46
> Perlite                                   2.6

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