Using Silica - what's the real scoop? Contradictory info everywhere

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phxazcraig

phxazcraig

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I've been following various grow guides both here and at cocoforcannabis.com. I've gotten great advice, and my plants are looking fabulous. First grow in coco coir, and plants are about 7 weeks, 2 into flower.

All along I've been using Silica Blast at initially 2.5ml/gallon. (I mix 10 gallons, dump into a 14 gallon container and often top up with some RO water that might have some cal/mag in it. I do this to reduce EC as I'm feeding 5x/day anyway and don't need high EC.)

I mix the Silica Blast first, then wait an hour, then add cal/magic, GH nutes, and finish with some humic acid, yucca powder and finally some h2o2. I adjust the pH to 6.0 and keep it there with a Bluelab controller.

Now for the questions:
1. pH: I've seen a couple of articles on general use of Silica that state it won't stay in solution with a pH under 7.0. True? I'm at 6.0.

2. Delay after adding: I've seen virtually no mention of mixing Silica and waiting before mixing other nutes. I have seen articles that mention mixing it separately, and I've seen articles stating to add it at the end of mixing up nutes. And I've seen various forum messages stating it being added at the end as a pH increaser and not much more.

Where is this 1 hour delay coming from, and is it universal or only apply to specific Silica formulations? In particular is my Silica Blast any different? It mentions nothing about interaction with other nutes on the bottle.

3. Quality of flower without Silica" I ran across an argument that basically said your flowers would smoke better if you discontinued silica at some point during flowering. Thoughts?

4. Interaction with nutes: There seems to be a clear dichotomy of views depending on where you look. Don't add it to nutes because it causes some sort of problems versus add away, no issues mentioned.

Hoping for some clarification here. I'd like not to have to wait that hour...
 
Peat_Phreak

Peat_Phreak

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What you are using is Potassium Silicate. What you want to use is bio-available Silica in the form of Silicic Acid. Such as Power Si. Then you don't have to worry about your bullet points.


What you are using now is not immediately bio-available, it raises media pH over time and interacts with other nutes. And yes, you should let it sit with water for at least 10 minutes before adding other nutes.
 
PipeCarver

PipeCarver

Supporter
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What you are using is Potassium Silicate. What you want to use is bio-available Silica in the form of Silicic Acid. Such as Power Si. Then you don't have to worry about your bullet points.


What you are using now is not immediately bio-available, it raises media pH over time and interacts with other nutes. And yes, you should let it sit with water for at least 10 minutes before adding other nutes.
Just to add to that...... it allows time for the silicate to break down and become accessible to the plants & other nutes. . I was told to add first and wait 10 -15 min as its like a jello.. ( even though it may look liquid ) and it needs time to dissolve and after the wait stir vigorously as it may have settled then add the micro and so on.........I don't use cal/mag. so I'm not sure where that would work in....
 
frankreynolds

frankreynolds

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Stabilized mono silic acids need to be quite acidic to be stable as they claim, once added to a res for plants around ph of 6 you lose stability. Just like when you reduce potassium silicate from it's alkaline state.

From everything I have read, it indicates potassium silicate consistently fed via root application will lead to higher levels of silica in the plant. In my opinion Potassium silicate is still the best to add when you are root feeding as long as you can deal with the PH and extra potassium (IMO not a huge deal).

Stabilised Mono silicic acid products seem to be really geared towards foliar feeding.

Something to ponder is how much Silica can Cannabis uptake? It is not like rice and other grain crops that uptake large amounts of Silica.
 
J

JarJar

2
1
When I asked hydrobuilder why there is no Silica in UC nutrient line, they replied that Silica will only stay dissolved at higher ph. So, this is a pertinent question. How do we add Silica, if it is the growers goal, with that ph variable in mind? I plan on researching it but perhaps someone can chime.
 
phxazcraig

phxazcraig

527
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When I asked hydrobuilder why there is no Silica in UC nutrient line, they replied that Silica will only stay dissolved at higher ph. So, this is a pertinent question. How do we add Silica, if it is the growers goal, with that ph variable in mind? I plan on researching it but perhaps someone can chime.
I'm using Silica Blast, which is labeled for hydro and coco. The last line of the instructions are to set pH to 6.0.
 
C

CookiesLikeWhoa

164
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I've been using Power SI during the veg phase and Power SI Bloom for the first 5 weeks of flower (going to stop now as I'm dealing with lockout issues) and can say compared to my previous grow the stems and stalks are just logs now. Ultimately once it's dried and chopped we will find out how much of a difference.

The thought I'm going through is whether or not to utilize it as a foliar spray or not, and then if to use it as a foliar spray, is it in addition to using it in the feed (currently rocking .6ml/gal of Power SI, and 1ml/gal of Bloom) or in lieu of the feed. Anyone had experience with foliar sprays?
 
Neuro

Neuro

If you plant ice, you're gonna harvest wind.
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I mix silica, then calmag, then nutes. I never wait an hour. The results are obvious; stronger stems. I stop using silica around week 7 flower. I don't use humic acid, studies show it significantly decreases thc.
That's a horrible study that doesn't at all show that humics are bad for THC levels. Their light schedule and environmental conditions were all out of whack, they were pushing insane amounts of humics at levels no one I know comes close to using. They were using low THC plants to begin with ( controls came in at ~12%). They also didn't examine any other cannabinoids or terpenes. That paper is just bad science. I wish they had done it well because it would have been fascinating.
 
Ponky

Ponky

3,606
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I wonder if you had a bad batch. The stuff I use makes a huge difference in stem strength and bud density. It's not a small difference; its very apparent.
I've gone through more than one bottle. Always armor Si. But I realized when I didn't use it there was no difference. Weight and density and potency remained consistent. I guess I could do a side by side for my next one. Revisit it.
 
growsince79

growsince79

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I've gone through more than one bottle. Always armor Si. But I realized when I didn't use it there was no difference. Weight and density and potency remained consistent. I guess I could do a side by side for my next one. Revisit it.
Don't know about armor, but the results I get using cyco is very obvious - amazing difference in stem strength.
 
E9noxis

E9noxis

1,092
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I used to use potassium silicate then someone on here said it's not available to the plant for almost 2 months while it breaks down. The I got silica gold from TPS.

My stalks are wood. I dont know if the p.silicate had anything to do with it, but I dont have much play on my branches.

Because of the slow breakdown, I wonder if I can use the potassium silicate as a soil ammendment for maybe a slow release. I dont know. I have pulled that trigger yet.

I also stopped adding the silica when I flipped to flower. The only thing I add now is bloom booster and calmag. Next week (week 5) I will start adding signal terpene enhancer. I hope that does something.

I also will not spray anything on my buds. Seems gross. I will drought flush and go dark before harvest.
 
Blastfact

Blastfact

748
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I've been using Silica for years. The last 4 plus years it's been NPK Ind. Raw Silica starting at 1/8 tsp per. gallon at two weeks. Then switching to 1/4 tsb per. gallon at four weeks until two weeks before harvest. I mix the RAW in with my regular weekly fortified water which is the silica, cal-mag and molasses. I also use Mad Farmer Silica as a foliar feeder starting at 4 weeks mixed 1/4 tsp per. quart until buds show. Silica has been really helpful with leggy sativas with good stalk and stem development. Very noticeable across the board in all plants when I don't use it.
 

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