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Old 13-07-2004, 12:02 PM
Aaron Hicks
 
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Default Would this work for orchids?

These compounds (polyacrylamide and polyacrylate polymers) go by
the generic name "superabsorbent polymers," or SAPs. They can hold several
hundred times their own weight in water. The ones featured are probably
the potassium polyacrylate polyacrylamide copolymer.

Their purposes include everything from "pigs" used in firefighting
to absorb spills, the packing in diapers (tear one apart and look for the
hard, grainy crystals), magic tricks, and some agricultural purposes that
crop up every couple of years or so.

While they may have certain limited applications in agriculture,
their use with orchids is minimal. These cystals expand and contract as
they absorb or release water, so they shrink and grow. The net upshot is
that anything that does so will eventually wash out of your bark media and
onto your greenhouse floor (don't slip on 'em). For epiphytic species that
require lots of air circulation, this renders them useless. Even if they
could be retained within the media, epiphytic orchids generally die from
too much water, rather than not enough. SAPs in this context would prove
to be counterproductive.

In the other application (terrestrial plants), they would retain
too much water. There are plenty of other non-synthetic compounds that are
capable of doing the exact same thing for a whole lot less money and
trouble.

It is worth noting that the markup on these products is huge; they
can be purchased on an industrial scale for tens of dollars per hundred
pounds. Then they're re-packaged for everything from watering crickets for
the pet trade to fancy flower-holding materials at the crafts store for a
few bucks per ounce. They aren't toxic in the polymer form, but the
monomer (acrylamide) is nasty stuff; I'm not sure that the breakdown of
these compounds in a confined, organic (reads: greenhouse) setting has
been well-explored.

As an aside, I tried them as substitute gelling agents for plants
_in vitro_. Although I won't discount the possibility that the autoclaving
changed them somehow, 6 permutations I tried killed orchids dead. Another
two were *almost* useful, but didn't compare well at all to the control
(agar).

I just don't see the upside to using SAPs with orchids. If anyone
has one that can beat (pound per pound) stuff like sphagnum, I'd sure like
to hear it.

The e-mail address in the header is a spam trap. Send no mail
there.

Cheers,

-AJHicks
Chandler, AZ


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Old 14-07-2004, 01:05 PM
Dave Sheehy
 
Posts: n/a
Default Would this work for orchids?

Ray ) wrote:
: Dave,

: You need to think about Aaron's "shrink and grow" comment. I think it's a bad idea under a plant or
: pad of moss.

Yeah, I have been thinking about that. I bought some of this stuff to play
around with but I haven't actually used it on a plant yet. The stuff expands
a *lot* when you soak it in water. But, it doesn't soak up water and expand
very quickly so in practice I wonder how much expansion you're really going
to see. Unless you soak the plant in water for quite awhile (a practice which
I don't follow) there's not going to be enough water available for long
enough to allow for maximum expansion. Given that you gotta start wondering
if there's any benefit. Remember, I'm only looking for a day or two more
water retention so maybe it will be enough. It's time for another experiment
methinks. I think I'll spread some crystals over a bed of damp sphagnum and
see how much water it absorbs over time. That should give some indication of
how it will behave in real conditions.

Dave

: --

: Ray Barkalow - First Rays Orchids - www.firstrays.com
: Plants, Supplies, Books, Artwork, and Lots of Free Info!

: . . . . . . . . . . .
: "Dave Sheehy" wrote in message
: ...
: Aaron Hicks ) wrote:
: : These compounds (polyacrylamide and polyacrylate polymers) go by
: : the generic name "superabsorbent polymers," or SAPs. They can hold several
: : hundred times their own weight in water. The ones featured are probably
: : the potassium polyacrylate polyacrylamide copolymer.
:
: snip
:
: : While they may have certain limited applications in agriculture,
: : their use with orchids is minimal. These cystals expand and contract as
: : they absorb or release water, so they shrink and grow. The net upshot is
: : that anything that does so will eventually wash out of your bark media and
: : onto your greenhouse floor (don't slip on 'em). For epiphytic species that
: : require lots of air circulation, this renders them useless. Even if they
: : could be retained within the media, epiphytic orchids generally die from
: : too much water, rather than not enough. SAPs in this context would prove
: : to be counterproductive.
:
: snip
:
: : I just don't see the upside to using SAPs with orchids. If anyone
: : has one that can beat (pound per pound) stuff like sphagnum, I'd sure like
: : to hear it.
:
: Here's an application of this stuff that I've been considering. I grow
: indoors in a window sill. A number of those are mounted orchids that
: hang in the window sill. I've packed all those orchids with wads of sphagnum
: in order maximize moisture retention. Even at that they still dry out
: within a day or maybe two. For some types of orchids (e.g. Cirrhopetalum,
: Encyclia, and Brassia) I'd like to get this up to 3 or 4 days (not sopping
: wet but ideally somewhat damp). My thought is to incorporate this material
: inside or underneath the sphagnum wad with the idea being that the polymer
: will release its moisture and keep the sphagnum hydrated.
:
: I do worry about how well the sphagnum will retain this stuff and how the
: cyclic shrinking and growing will hold up.
:
: Dave Sheehy
:


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Old 15-07-2004, 02:02 PM
Ray
 
Posts: n/a
Default Would this work for orchids?

Dave,

You need to think about Aaron's "shrink and grow" comment. I think it's a bad idea under a plant or
pad of moss.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!

.. . . . . . . . . . .
"Dave Sheehy" wrote in message
...
Aaron Hicks ) wrote:
: These compounds (polyacrylamide and polyacrylate polymers) go by
: the generic name "superabsorbent polymers," or SAPs. They can hold several
: hundred times their own weight in water. The ones featured are probably
: the potassium polyacrylate polyacrylamide copolymer.

snip

: While they may have certain limited applications in agriculture,
: their use with orchids is minimal. These cystals expand and contract as
: they absorb or release water, so they shrink and grow. The net upshot is
: that anything that does so will eventually wash out of your bark media and
: onto your greenhouse floor (don't slip on 'em). For epiphytic species that
: require lots of air circulation, this renders them useless. Even if they
: could be retained within the media, epiphytic orchids generally die from
: too much water, rather than not enough. SAPs in this context would prove
: to be counterproductive.

snip

: I just don't see the upside to using SAPs with orchids. If anyone
: has one that can beat (pound per pound) stuff like sphagnum, I'd sure like
: to hear it.

Here's an application of this stuff that I've been considering. I grow
indoors in a window sill. A number of those are mounted orchids that
hang in the window sill. I've packed all those orchids with wads of sphagnum
in order maximize moisture retention. Even at that they still dry out
within a day or maybe two. For some types of orchids (e.g. Cirrhopetalum,
Encyclia, and Brassia) I'd like to get this up to 3 or 4 days (not sopping
wet but ideally somewhat damp). My thought is to incorporate this material
inside or underneath the sphagnum wad with the idea being that the polymer
will release its moisture and keep the sphagnum hydrated.

I do worry about how well the sphagnum will retain this stuff and how the
cyclic shrinking and growing will hold up.

Dave Sheehy



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Old 18-07-2004, 11:03 PM
Dewitt
 
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Default Would this work for orchids?

On Mon, 12 Jul 2004 06:26:14 -0400, "RPM1"
wrote:

http://www.planthealthcare.com/catal...errasorb3.html

Just wondering.

Ruth CM


In general, we want orchids to have excellant drainage and gels like
this that hold moisture would be bad idea. You might be able to use
it with a few terrestrials like Ludisa discolor but I wouldn't
recommend it.

deg
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Old 19-07-2004, 12:03 AM
Rob Halgren
 
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Default Would this work for orchids?

RPM1 wrote:

"Dewitt"


In general, we want orchids to have excellant drainage and gels like
this that hold moisture would be bad idea. You might be able to use
it with a few terrestrials like Ludisa discolor but I wouldn't
recommend it.



I'm thinking of it more to augment planting mixture rather
than =be= the planting mix exclusively. Maybe a layer
or two of it in the pot with the regular mix.

Ruth CM


I just mixed it in, Ruth. Make sure you hydrate it before you pot,
otherwise your mix will explode out of the pot the first time you
water. I think the recipe I used was something along the lines of
4 bark
1 sponge rock
1 charcoal
0.5 hydrated "goo pellets" - the larger the grade the better.

Plus or minus a few parts. A friend of mine called the gel "horse
boogers". Close enough. I probably still have some in the basement
somewhere. It worked OK for paphs and phrags, but (like everything else
I use for paphs) it needs to be changed at least every 18 months. Two
years is death. One year is probably best. I'd say the water holding
function was nice, but the main problem was that the gel contracts when
it is dry (to a very small size) and expands when wet. That makes for
some interesting media shifts, especially if you let the mix dry out
well between waterings - which we usually do. Eventually the stuff just
dissolves, and it probably was all gone after the first year.

Anyway, I tried it for long enough to figure out I didn't really
like it. I don't repot that often, so I probably had a few plants in it
for a couple years. I think I can get the same water holding function
from coconut husk, or by adding milled sphagnum or chunky peat to the
mix. I understand them better, and in my hands those 'natural'
components are easier to work with. I'm particularly fond of the
coconut, because it doesn't change shape or size when wet, and it holds
onto water forever. Squeeze a piece a week after you water, and you can
still coax some liquid out.

Now, if you were growing in a totally hydroponic system, the water
gel might make an interesting substrate. Of course it wouldn't be
totally hydroponic anymore... But it might give some support to the
plant. I think it would still break down too quickly to be worth it,
but it might be an interesting experiment.

Just my $0.02.

Rob

--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a. See rule 1
3) When one has insufficient credit to purchase
more orchids, obtain more credit
LittlefrogFarm is open - e-mail me for a list )


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Old 19-07-2004, 12:03 AM
Rob Halgren
 
Posts: n/a
Default Would this work for orchids?

The Doormouse wrote:

"RPM1" wrote:



http://www.planthealthcare.com/catal...errasorb3.html



It seems like a great idea for keeping the roots moist, but what about air?


No reason you couldn't put some in a tray, add water, and blow air over
it. I don't know exactly why that would be more efficient than just
blowing air over a tray of plain water, though.

The Doormouse



I've tried this stuff in potting mix before. It is ok, I guess, but get
the biggest 'grain size' you can. It didn't kill my plants. Why?
Because I am a terrible waterer, and I never water often enough. I
suspect any 'normal' person who uses one of these water retaining gels
is asking for trouble. I wouldn't use it now, since I use largely
coconut husk as my media base - that holds a heck of a lot of water
already. Looks pretty darn goofy, like a herd of transparent slugs are
swimming in your pot.

Rob

--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a. See rule 1
3) When one has insufficient credit to purchase
more orchids, obtain more credit
LittlefrogFarm is open - e-mail me for a list )
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