You’re very perceptive. I’m surprised you remember that short portion of our conversation. The non-profit food bank garden employing under-served members of the community didn’t pan out, but cannabis consulting certainly did. Thank you for your reply.
EDIT: I really like the simplicity of your silica recipe. I almost forgot to change my Hydrobuddy P and K inputs.
Used at 8mL gal it should provide around 20ppm of Si As SiO2, 40 ppm of P and 10 ppm of K.
I used your formulation and everything went smooth. I substituted phosphoric acid for sulfuric acid with no issues. 10g of technical grade 96% sulfuric yielded 1.6pH.
How important is the pH of the stored solution? Ideally for fertigation I would prefer to run the pH of the solution higher to avoid using a base later in the process. Everything was water clear before adding acid.
Awesome Great to know it works with sulfuric acid. The pH of the concentrated solution needs to be kept below 2. If you increase the pH of the concentrated solution then the Si species are still likely to polymerize due to their high concentration. When diluted for use in hydroponic solutions they should be stable at the 10-50 ppm of Si as elemental Si generally used.
I will however measure the stability this coming month when I go to Bruce’s lab and confirm to you whether they actually are more bioavailable than when you just prepare a hydroponic solution using potassium silicate stocks.
@Flowerman Thanks for the DIY advice on making this stabilized 4% orthosilicic acid.
Did you end up finishing up your SOP for 4 and 6% blends ?
I have tried my best to follow your guide and upon adding the silica it clouds up, forms crystals, and is not nice and clear like what you have achieved.
Can you expand upon you notes section, i dont understand most of t the notes. I used a magnetic stirrer to mix all ingredients. Why do you suggest the rinsing part using 5ml of water?
I dont have AgSil but i have Potassium Silicate powder and also a liquid version that contains a total Potassium (K) (as silicate) 15.3% and Silicon (Si) 17.3%.
First batch I dissolved the powder as per directed. It didnt fully dissolve and the batch went very cloudy when i added it (on a cold bath) and it went separated.
Second batch I used the liquid (only 10ml) as i didnt know what the equivalent would be to your 10g of AgSil16H. It also went cloudy and still has small crystals not dissolved.
If I can find 500 lbs of sorbitol, I’ll run it on 1 house for 2 months at 8ml per gallon. Ironically I’m already currently running agsil at 20ppm SiO2. The house next door would stay on agsil, so it should be a pretty fair comparison.
@emdub27 I just had one of the first batches I made of this gel after 3 weeks. I would test a small amount under the conditions you are going to use and verify it can remain stable before making any large amount of it.
I had a kilo of sorbitol, so I made 3500ml. I did a foliar of it yesterday at 10ml per gallon (same rate as AB Yellow) on about 7,000sf of flower canopy and about 2,000sf of veg canopy. It perked the plants up just like AB yellow does.
I’m enthusiastic about trying it in a continuous drench at 20ppm SiO2 because I’ve never had the opportunity to test that high of a concentration of silicic. I fill stock tanks once a week, so I should be able to work around a 3 week gel time. It looks like I found sorbitol for about $2 a pound, so $1k to test for a full flower cycle, I can stomach because even of it improves yield by half a percent, I’m ahead.
I did several phytotoxicity tests on Friday. As expected simply diluting it with water and 80/20 surfactant caused some burning due to the acidic nature. pH corrected to 6.4 ( where I foliar most things to not disrupt sap pH) there were no issues. Also tested a tank mix of silicic and soluble kelp that mixed to 8.4 pH the higher pH did not appear to reduce efficacy.
Edit: also used 80/20 surfactant at 6.4 pH and with the kelp rank mix.
Exciting to see someone else testing it large scale.
Would adding some glycerol or carnitine HCL prevent the 3 week gelling ?
What surfactant did you use (polysorbate 20?) i have used it before but even at small % it foams up so much !
My test res gelled in two days and the ph dipped to 5. My ec was 2. I used phosphoric to make my stock solution and used it at only 200ml to a 50gal res. Maybe it’s cus I still had agsil in there too for ph adjustment?
Surfactant used was tractor supply 80/20 wetting agent. I’m a cheap bastard and it’s $20 a gallon.
My chemistry knowledge with Si is not strong enough to speculate on how to make it more stable. I do know that polyvalent cations like boron are used as stabilizers in some formulations like PowerSi.
At 10g of Sulfuric to 700ml, the addition of S is about 12 ppm when used at 10ml per gallon.
I setup all dosers to run 1:100, so I have no intention to make it any stronger. I would actually need to dilute it to inject it.
I have not jar tested with a fertigation solution yet. I’ll probably set one up later today.
I did an experiment this morning foliar feeding with a hose end sprayer set at 2oz per gallon. For a total volume of roughly 1000ml, I added 160ml of the Silicic stock solution, 50g Cal Acetate and 25g KNO3. Silicic mixed in first, cal acetate and KNO3 were pre dissolved and added together. It mixed water clear to 6.3 pH with no additional pH correction. I observed no precipitation or anything else alarming, it was applied to Veg about an hour ago.
Great to know it works with sulfuric acid. The pH of the concentrated solution needs to be kept below 2. If you increase the pH of the concentrated solution then the Si species are still likely to polymerize due to their high concentration. When diluted for use in hydroponic solutions they should be stable at the 10-50 ppm of Si as elemental Si generally used.