[aka23]

Hello,

I am on the forum because I'm working on a project and need some help. Hopefully I'm in the right forum, if not maybe someone will move my post.

I would like to make a clear thixotropic gel as substitute for soil. I'm sure some of you have seen plants growing in a clear gel or ant farms that are made in a clear gel. That gel is what I'd like to make. I have looked up some patents, but it hasn't really yielded any answers. There are a lot of patents regarding plant gel, but the patent articles are a translation which makes it difficult to understand. I was wondering if anyone else could help. I found a patent and it mentions magnesium silicate; however, it doesn't really state any other additives other than nutrients for plant growth. Here is the link- http://patents.justia.com/patent/20080216404.  Could it be that the gel is just magnesium silicate without anything else or would there be other proprietary information missing in the patent? It seems that there is more to the process.  I believe NASA patented a gel growing medium, but I couldn't find any information on it.

I know that there is another product called Nafion, but it's incredibly expensive. If anyone has any alternative ideas or more information please share!

[Arkcon]

I've had good results making hydroponic media out of the so called "water crystals" often used to keep moisture in plant pots.  When fully hydrated outside of soil, the polyacrylamide gels suitably bulky and pretty.  A little pricey, but if you can make it work on small scale, then you'll know what to ask for if you want to do more.

[aka23]

I've had good results making hydroponic media out of the so called "water crystals" often used to keep moisture in plant pots.  When fully hydrated outside of soil, the polyacrylamide gels suitably bulky and pretty.  A little pricey, but if you can make it work on small scale, then you'll know what to ask for if you want to do more.

Yes, I've seen the "water crystals". What happens with those is that they seem to get into independent globs and it doesn't make the it really clear cause of the all the refraction.... I would like the substance to be clear like the photo I attached. Maybe if I just fully hydrate it and not move it will end up like the the photo? would it be toxic ?

[Burner]

How large is your plant? If it's very small, agar plate can be used.

[Intanjir]

Fun project.

You should try out using just silica.
A wet silica hydrogel will be sufficiently translucent as long as it is almost entirely water.
All you need is cheap waterglass, or alternatively fumed or colloidal silicas.

I have made many a jelly and I promise it isn't hard.
Just dissolve the waterglass with very hot water but only use a small amount of water to keep the pH maximized for a good dissolution. Once fully dissolved filter any reticent bits of glass and dilute to your desired concentration. Then combine with a solution of your favorite acid and wait.

Drying out may be a problem. If you let it dry too much you cannot reconstitute it back to a gel.
This could be mitigated with a narrow necked vase or with hygroscopic additives.

I have never tried adding water to an already formed dilute gel to see under what conditions it would eventually expand and absorb the water or if it would always remain separate.
I know that silica gels often exhibit syneresis, so it seems likely that added water will remain on the top as a separate layer.
In any case, as long as it was dilute enough you could always vigorously stir new water into the gel.
I do note that people don't normally stir their houseplants...maybe just grab the stalk and twist the plant around and let the roots do the mixing?
Hard to do in soil but not so hard in gel.
Alas, air bubbles would get entrained.

[aka23]

Thanks for taking the time to comment. I will look into your suggestion and see if I can make it. So i can get colloidal silica and just dissolve it in hot water until I get the right consistency while mixing in an acid and that will create my transparent medium?

[Intanjir]

I'm not quite sure what you mean.

If you are suggesting that you might purchase 'colloidal silica' then that will come as a suspension and thus would not need to be 'dissolved'. The suspension will be prevented from gelling during transport and storage by having some alkaline agent as a stabilizer. It will also be more concentrated than you will want in the end. If you neutralize it to the right pH with an acid and/or if you introduce just enough, but not too many, positive ions as a salt then you can get it to gel. If you are too heavy handed about it then it will happen too quickly and you will get flocculated precipitate instead.
So just play around with samples by adding various amounts of water, acid, and possibly salts and just wait and you will have yourself some fine jellies .
As long as the silica content is low the transparency should be high.
Temperature isn't a necessary parameter to fiddle with if you are starting out with colloidal silica.


The instruction I gave before was for sodium silicate. With that you will want to use very hot water to get it to dissolve initially. Then you dilute it, add dilute acid, and wait. You will either form a gel in the one step or you will form a colloidal suspension which you can then get to gel by adding a bit more acid or by adding salts.

I've only ever made my own colloidal suspensions from sodium silicate(easy) or from fumed silica(harder).