water absorbing polymers/crystals

[fbrem]

I recently got some seedlings with this stuff in the mix. I was amazed at how long the media in those little pots remained moist and thought maybe this stuff could be useful for our hot dry summer months. Is anyone familiar with this stuff? any negative effects other than possibly averwatering? does it breakdown quickly? any opinions?

Forrest

 

[Ernie]

Forrest,

I probably wouldn't use them for most epiphytic orchids, but Phaius and jewel orchids might like it in dry conditions.
My wife got me one of those topsy turvy upside down tomato containers, and I foresee the biggest issue with it being fast drying so I'll probably use some in it.
What is it? It's called hydrogel. A very porous polymer (plastic) that can hold tremendous amounts of water. They shrink down as they dry and swell up as they wet. Sort of like a kitchen sponge. Not exactly sure of their chemistry (looks a lot like diacrylated Polyethylene glycol to me) (would dictate their longevity), but most commonly used hydrogels are made of pretty stable chemicals that can dry and wet MANY times with no degradation.

-Ernie

 

[Ray]

They are acrylate polymers, and apparently nontoxic. Fertilizer chemicals will break them down more rapidly than will plain water.

The biggest issue is that the globs of polymer change size as they swell upon absorption and shrink as they dry out. Such action moves the medium particles around leading to more dense packing.

 

[wilbeck]

The latest edition of "Fine Gardening" had a piece about this stuff and found that it made little, if any difference. There was a thread about this a while back: http://www.slippertalk.com/forum/showthread.php?t=6701

 

[Leo Schordje]

Ray's comment is right on, I tried some of these polymers - it is difficult to get the right amount in a mix - too much and the plant gets heaved out of the pot by the swelling & shrinking as you alternate from wet to dry. Other particles in the mix pack tight and the mix looses air voids. I definitely lost roots to rot with a number of my test plants. BUT I have seen one grower use it in her outdoor beds - for dirt plants with good success.

 

[Ernie]

I was going to buy some of these beads for my tomatoes and peppers, but didn't because I felt $10 for a pound was too expensive... So yesterday was warm and sunny, and my 2.5 y.o. son and I were running through the sprinkler in the back yard, and his britches looked like they were going to bust open. Not a surprising fact considering he was wearing a pull up diaper. (Not to brag, but he is almost 100% potty trained, but we put a pull up on him if we might end up somewhere distant from a toilet- namely, playground). It occurred to me this morning that one could probably use the gel from a diaper the same as these beads. I'd guess a little bit would go a long way since a clean, dry diaper weighs about the same as a couple sheets of paper, but a completely wet one is about 100 pounds. Nitrogen supplementation is possible too. Any comments?

-Ernie

 

[likespaphs]

... Nitrogen supplementation is possible too. Any comments?
-Ernie

my only comment is, dude! gross!

 

[Jim Toomey]

Congrats on the "almost potty trained" at 2.5 years that is awesome!
We are going to tackle that one this summer for my 2 y.o..

 

[Ray]

"Potty trained" is nothing. Just wait for "driver trained" and "money trained" in college.

 

[snow]

very funny story Ernie.
in our days we used cloth diapers.

 

[Ernie]

very funny story Ernie.
in our days we used cloth diapers.

No, I don't think cloth diapers would hold water for veggies very well.

-Ernie