Grow-Sil for silica, is it any good?

[Chris Edward]

Hello all,

I just recently found out about this stuff called Grow-Sil, which is made from rice hulls and boasts a soluble silica amount of 99.9% and a pH of 7.0
Has anyone used this before?
Is it like AgSil-16H?

It appears I can swap the two out and use about half as much of the Grow-Sil as I was using of the AgSil-16H and it won’t have as big an effect on pH, which is always a plus.

I was using Grotek Pro-silicate, but then I found AgSil-16H, which is the same thing (potassium silicate), but in powder form and it costs 56% less.
A 1 liter bottle of Pro-silicate costs about $15.
A 1 pound bag of AgSil-16H costs $20 and can make 3 liters.

AgSil-16H has about 52% soluble silica and 4% potassium and the mixture is very alkaline, so you have to add it to your source water first, then add pH down and then add your fertilizer.
If you add the fertilizer first, then add the AgSil-16H, it will cause the nutrients to fall out of solution (namely calcium).

If I can swap out the Grow-Sil then this would be an additional 47% savings on the AgSil-16H, so the per liter cost will go down to something like $3.54

That would be awesome!
I use a lot of silica…

While we’re all here, what silica do y'all use?
How does it work for you?


Thanks for you help…

 

[Lordhooha]

Hello all,

I just recently found out about this stuff called Grow-Sil, which is made from rice hulls and boasts a soluble silica amount of 99.9% and a pH of 7.0
Has anyone used this before?
Is it like AgSil-16H?

It appears I can swap the two out and use about half as much of the Grow-Sil as I was using of the AgSil-16H and it won’t have as big an effect on pH, which is always a plus.

I was using Grotek Pro-silicate, but then I found AgSil-16H, which is the same thing (potassium silicate), but in powder form and it costs 56% less.
A 1 liter bottle of Pro-silicate costs about $15.
A 1 pound bag of AgSil-16H costs $20 and can make 3 liters.

AgSil-16H has about 52% soluble silica and 4% potassium and the mixture is very alkaline, so you have to add it to your source water first, then add pH down and then add your fertilizer.
If you add the fertilizer first, then add the AgSil-16H, it will cause the nutrients to fall out of solution (namely calcium).

If I can swap out the Grow-Sil then this would be an additional 47% savings on the AgSil-16H, so the per liter cost will go down to something like $3.54

That would be awesome!
I use a lot of silica…

While we’re all here, what silica do y'all use?
How does it work for you?


Thanks for you help…

Do you growin soil? If so I would say there’s plenty in the soil already.

 

[Chris Edward]

@Lordhooha,
No, I grow in hydro.

You shouldn't assume the soil you are using has enough silica. There may be sand in the soil, but this isn't bio-available silica.
It works wonders for plant stress and nutrient absorption, especially in the summer.

There are a lot of uses for soluble silica, the list goes on and on from helping with plant stress, to the powder being able to be used like diatomaceous earth and it seems like more uses are being found all the time.

I recently read about how it can be mixed with neem oil additions, so the silica slices into the insects so the neem oil can be more effective.
Then the silica is absorbed into the leaves and creates a barrier (of sorts) for the next time insects come around.

It's pretty cool stuff.

 

[Lordhooha]

@Lordhooha,
No, I grow in hydro.

You shouldn't assume the soil you are using has enough silica. There may be sand in the soil, but this isn't bio-available silica.
It works wonders for plant stress and nutrient absorption, especially in the summer.

There are a lot of uses for soluble silica, the list goes on and on from helping with plant stress, to the powder being able to be used like diatomaceous earth and it seems like more uses are being found all the time.

I recently read about how it can be mixed with neem oil additions, so the silica slices into the insects so the neem oil can be more effective.
Then the silica is absorbed into the leaves and creates a barrier (of sorts) for the next time insects come around.

It's pretty cool stuff.

I build mine it has more than enough. But pretty much any good soil made for container growing is going to have enough. Hydro Is the only instance I’d use silicate.

 

[Chris Edward]

@Lordhooha,
I don't mean to harp on the topic, but unless you are adding some form of silicic acid, or you have had your soil tested and know it is contains "enough", don't assume that any "good" soil has the appropriate amounts of water soluble silica, without knowing the actual content.

I am not suggesting you don't know, all I am saying is that people shouldn't just assume that the bag of soil they bought contains enough silica, especially if that soil has been re-used.

This is something farmers are just now beginning to wrap their heads around.
At a fertilizer conference for farmers in November 2017 the concept was brought up during a presentation and most of the farmers there just assumed that their soils had enough bio-available silica.

 

[xtsho]

Regardless of growing media, silica is a waste of time. Don't worry about it.

Use the

Keep It Simple

Method

Guaranteed better grows.

 

[xtsho]

@Lordhooha,
I don't mean to harp on the topic, but unless you are adding some form of silicic acid, or you have had your soil tested and know it is contains "enough", don't assume that any "good" soil has the appropriate amounts of water soluble silica, without knowing the actual content.

I am not suggesting you don't know, all I am saying is that people shouldn't just assume that the bag of soil they bought contains enough silica, especially if that soil has been re-used.

This is something farmers are just now beginning to wrap their heads around.
At a fertilizer conference for farmers in November 2017 the concept was brought up during a presentation and most of the farmers there just assumed that their soils had enough bio-available silica.

You are over thinking things way too much.

 

[Chris Edward]

@xtsho,
Normally I would totally agree with what you have to say, but I have seen so many positive results using silica.
Especially during summer time.
I can now grow pretty much anything I want all though the year and the silica helps the plants deal with the heat stress or low humidity or whatever the temp extremes here throw at them.
With silica, lettuce takes much longer to bolt in the summer, allowing me a perfect window to grow and harvest before the first flower stalks even begin to shoot up.
Prior to using silica, summer was a total shutdown period because what did grow would eventually get root rot or would be so infested by thrips that the plants would have to destroyed.

Like, I said, normally I would agree with you, but I have seen the results, so I know it works.

 

[WeedZen]

If your using fresh soil each time then as Lordhooha said it would have enough already but you are correct about silica needed in soil especially if you reuse your soil or have a type of super soil because it will deplete over time. I can't give you much feed back on AgSil-16H but I do use Grotek Pro-silicate and really like the fact it's in liquid form and simple to use, less PITA factor. I don't think your going to see any difference in the two as silicate is silicate and the plant will utilize it if available.

 

[Lordhooha]

If your using fresh soil each time then as Lordhooha said it would have enough already but you are correct about silica needed in soil especially if you reuse your soil or have a type of super soil because it will deplete over time. I can't give you much feed back on AgSil-16H but I do use Grotek Pro-silicate and really like the fact it's in liquid form and simple to use, less PITA factor. I don't think your going to see any difference in the two as silicate is silicate and the plant will utilize it if available.

There’s a lot that goes into my soil when I reuse. Composted diary poo, chicken poo and a host of other stuff. Never had an issue with bugs or growth.

 

[JohnDee]

Hi Chris,
I'm a believer in silica supplementation in hydro...and just bought some grow-sil.

Since you obviously have done research on the subject...I have a question for you.

Growing in coco and will be doing automated DTW. My intention is to give my additives separately hand watered to keep my res clean and simple. Would you think 2 to 3 times a week or should I add the silica daily.

Also, to get the powder mildow protection requires foliar feeding. You doing that too?
JD

 

[Chris Edward]

Hi Chris,
I'm a believer in silica supplementation in hydro...and just bought some grow-sil.

Since you obviously have done research on the subject...I have a question for you.

Growing in coco and will be doing automated DTW. My intention is to give my additives separately hand watered to keep my res clean and simple. Would you think 2 to 3 times a week or should I add the silica daily.

Also, to get the powder mildow protection requires foliar feeding. You doing that too?
JD

@JohnDee,
I don't grow in soil or soil-less media like coco.
I use self contained dutch buckets with hydroton as the media, so I am not really sure how silica will act in coco.

As far as how much silica to provide for your plants, that's a good question...
I would suggest 2 times a week with 0.2EC or 100ppm (NaCl conversion factor) of silica, but there is really a very large gap between "enough" and too much...
It's kind of like sulfur in that regard.
Because you are using a DTW system, I doubt there will be much of a build up.
In theory because you are using Grow-Sil, this is supposed to have a more neutral pH than AgSil-16H (Pro-Silicate, same thing...), so technically you should be able to add a lot more of this than I could of AgSil-16H (but you don't need to). This is because AgSil-16H is so alkaline and requires pH Down additions to bring the pH back to normal range.

On my last grow I just topped up my reservoirs with fertilizer that was 0.7EC or about 350PPM which was treated with AgSil-16H and pH'd to 6.5-ish before adding the fertilizer. I never flushed the reservoirs between topping off and to be honest, the yield this time around was exactly the same as when I use 1.4EC or 700PPM weekly refills, where I would pull the reservoir, flush it and add completely new nutrients (except for the few ounces that remains in the bottom of the dutch buckets).

If anything this grow was a bit more resinous then last time.

The best way to add the silica is by using a stock solution.
If you try adding the powder, you can very easily add way more than the plants will need and while I doubt this will have a negative effect on the plants, it will waste money.

The stock solution is usually between 7.8% and 10% (AgSil-16H), which mimics the Grotek Pro-Silicate.
Some of the silicates on the market are like 1-3% silica and are basically worthless (like Rhino Skin...)
By using Grow-Sil, you can use like 47% less which means a stock solution of 3.7%-4.7% will yield the same amount of silica as a 7.8%-10% solution of AgSil-16H.
So you would want to add 69.6grams of Grow-Sil per liter or 263grams per gallon of preferably distilled water.
This stock solution will keep, almost indefinitely.

From the stock solution you will want to use 5ml per gallon of source water.
5ml added to a gallon will be about 0.2EC or 100ppm's which is what you should shoot for.

A liter of the stock solution will treat 200 gallons of source water and a gallon of the stock solution will treat 757 gallons of source water, so a little goes a long way.

Again, because you are using Grow-Sil, you may not have to add any additional pH modifiers but this ultimately depends on your source water.


As far as powdery mildew, I have never had this issue so I cannot offer any help in that area.

I have heard that using silica as a foliar spray can fortify the leaves, especially against insect damage. The leaves will take the silica in and store it just below the surface, but not assimilate it; then later when an insect tries to eat the leaf it will be torn up by the silica.

I was planning on trying foliar spraying (with Grow-Sil) with the addition of neem oil during the vegetative phase to get rid of thrips. I don't dare try this with the AgSil-16H, it is too alkaline and may damage the leaves. The idea here being that the silica will cut the thrips and allow the neem to get into their systems easier.
I have also heard that you can use Grow-Sil as an emulsifier when mixing neem oil. I have been using a very safe commercial emulsifier which works great but it is extremely expensive, so if I can use the Grow-Sil, then when I spray for thrips, it won't cost nearly as much and it should do a lot more damage to the thrips.

Let me know what you think of the Grow-Sil.
From what I have been reading about this stuff, if it works as well as they say, then very soon, this may replace potassium silicate and the price should come down quite a bit.
I read an article where the patent owner boasted about how Grow-Sil costs like 90% less to produce than potassium silicate, and now more and more farmers are going to be using it, so we should see a slight price decrease soon as it becomes more mainstream. Then as the product gets closer to the end of it's patent, we should see the price go down a bit more.

 

[JohnDee]

Thanks Chris for the very complete answer...

You've given me a baseline dosage...and I can experiment from there. I like the stock solution idea. I'm doing that with my nutrients right now while I put together the irrigation system.

I've never had PM either. I didn't make that point clear. The claim that silica offers resistance to PM is only valid when the silica is fed via leaves. Not sure yet if I'll be doing that.

Nice to hear from someone who has seen real benefits from silica use. In my previous hydro grows I added a liquid silica product (don't recall which) and saw no difference. But like the Rhino skin you mentioned...it was probably way low on the silica %...
Cheers,
JD

 

[Chris Edward]

@JohnDee,
No problem.
I wouldn't be such an advocate for the stuff if I didn't see positive results from using it.
But it has to be used correctly or it can cause problems.

 

[JohnDee]

Chris,
Yes...the earth's crust is something like 1/3 silica and plants have always had access to it via soil. But there's no standard protocols in hydro...the one area where plants don't naturally have access to it.

I have a mish mash of medias right now but am using growstones for aeration since they leach silica. And when I fire up my old waterfarm...that's gonna be full of growstones too. Just because...and it will reduce the need for supplementation.

And any pure coco plants will get silica added from seedling stage on. So I think I have it covered.
JD

 

[xtsho]

I was looking at the Portland water quality analysis and noticed that the tap water I use has 4-4.5 ppm's of Silica (SiO2 as Si). Silica is present in most tap water at varying levels. Well water can contain up to 100 ppm's of silica. .

 

[JohnDee]

I was looking at the Portland water quality analysis and noticed that the tap water I use has 4-4.5 ppm's of Silica (SiO2 as Si). Silica is present in most tap water at varying levels. Well water can contain up to 100 ppm's of silica. .

Thanks for that xtsho...I live close to Portland but in Washington and the water quality report sucks. They only list contaminants and not natural minerals...
JD

 

[xtsho]

Thanks for that xtsho...I live close to Portland but in Washington and the water quality report sucks. They only list contaminants and not natural minerals...
JD

They have a pretty detailed analysis available online. Not the same across the river in Washington. I'm sure they have a complete analysis but for some reason they don't make it available online.

https://www.portlandoregon.gov/water/article/658060

 

[Chris Edward]

I was looking at the Portland water quality analysis and noticed that the tap water I use has 4-4.5 ppm's of Silica (SiO2 as Si). Silica is present in most tap water at varying levels. Well water can contain up to 100 ppm's of silica. .

@xtsho,
Portland is almost there...
You want about 100ppm for use on plants, 4-4.5ppm's of silica won't do much.

 

[Chris Edward]

They have a pretty detailed analysis available online. Not the same across the river in Washington. I'm sure they have a complete analysis but for some reason they don't make it available online.

https://www.portlandoregon.gov/water/article/658060

If you call your water company, they should be able to either direct you to a website, send you a PDF in an email or send you a physical water report.
They are usually pretty good about that sort of thing.
Make sure to check to see what form of disinfectants that they are using, don't assume they are using chlorine which will off gas on it's own in a day or two.
Some cities use chloramines and these are a little harder to get rid of and they won't simply off gas like chlorine.
One way to get rid of chloramine PDQ is to use an aquarium UV filter, this will break the bonds on the chloramines and allow them to off gas like chlorine. That coupled with moving the water around to ensure proper oxygenation, will get rid of the chloramine in an hour or two.

You can also use activated carbon, but then what do you do with the saturated carbon?
You can't compost it and once it is saturated it will begin to leach elements back into the water.

You can use potassium metabisulfate, which will break the bonds and allow the chloramine to offgas. You have to add so little that will probably not mess with your pH too much and it provides an alternate source of potassium.
This is added at about 35mg per gallon.
A pound usually costs between $4 and $10 and will be enough to treat over 12,000 gallons of water.
Just be careful, because it is an acid.
The sodium version is used in pools as a pH down and by jewelers to remove tarnish from jewelry.
I am note entirely sure if the potassium version can be swapped for the typical pH down (phosphoric acid) that is used in hydroponics, but it is worth a look into, because it is so much cheaper than typical pH down solutions.

Anyway, I digress...

People will suggest using citric acid, which works fast, but is also a short term method of sequestering the chlorine and chloramine. This is great for when you want to take a bath and you don't want the chloramine to soak into your skin, but after about a day or two the chlorine and chloramine will return. This also works for aquaponics systems that have the necessary bacteria colonies that can convert the chloramine into ammonium and then into nitrate which the plants can use.

If you have the time, you can boil the water for your plants for 20 minutes, this will get rid of the chloramine as well, but the water must be at a rolling boil for 20 minutes for it to be effective.

Sorry to go off on a chlorine and chloramine rant, but it seemed appropriate...