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Growernick's Harvest Gold Silica Performance Testing


Purpose of the Study:

To see the difference between plants given a high-grade silica nutrient vs those that do not receive the high grade silica. I’d like to see what differences in growth speed, vigor, yield, and subjective qualitative factors.


Do plants treated with HGS grow more robustly than those plants that do not receive the HGS?


Variable: 2 Lemon Betty cuttings will receive the Harvest Gold Silica (1 Lemon Betty will have HGS amended within the medium, 1 Lemon Betty will have the HGS amended on top of the medium).

Control: 2 Lemon Betty cuttings will receive no Harvest Gold Silica.

I will change very little else in my cultivation method. I will use Elite Nutrients for fertilization. I will utilize one Prism Lighting Science 315 watt light and a Phillips 930 3000°K lamp throughout the entire grow cycle. I will report my growth findings with pictures weekly.


1 3x3 Plant House grow tent
1 315 watt Prism Lighting Science Ballast
1 Phillips Agro 3100k 315 Bulb
1 Sun System RA Reflector
4 1 gal square plastic pots
4 10 gal Root Pouch fabric pots
2 2 cubic foot bags Batch 64 Pioneer coco mix
Elite Nutrients
Mammoth P
Enzymes Komplete
4 Lemon Betty clones grown in 1.5inch Grodan rockwool

GROWERS NOTE: Harvest Gold has generously made samples available to GNET members. If you are interested, reach out to get your sample! I want to make this study not only approachable in a meaningful manner, but also easy to replicate. If you have any questions, comments, or suggestions, please feel free to reach out to me, and I’ll be here to help the best I am able!

Study Commences January 25, 2018

Week One

Day 1: Rooted clones transplanted.

All plants receive Roots Gold from GH post transplant

  • PlantA has HGS on top of the Pioneer
  • PlantB has HGS with the Pioneer
  • PlantC has no HGS mixed with the Pioneer
  • PlantD has no HGS mixed with the Pioneer

Day 2: All plants receive feeding of Mammoth P

Day 3: Plants receive H20 with no NPK value

Day 4: Plants receive feeding of H20 with Hi Brix molasses

Day 5: Plants receive Elite Nutrients for NPK

Day 6: Plants receive H20

Day 7: Plants receive Roots Gold and Enzymes Komplete


HGS top dressing in Plant A is beginning to fully leach into the media. Plants all seem healthy and are growing uniformly. Transplant planned after two weeks

Week Two

Day 8: Plants receive H20.

Day 9: Dry day. Medium fully saturated in all plants at of day. NO WATER. FIM tops

Day 10: Plants receive Elite Nutrients for NPK

Day 11: Plants receive Mammoth P

Day 12: Plants receive Elite Nutrients and Hygrozyme

Day 13: Plants receive Pure H20

Day 14: (Feb. 10) Plants receive Mammoth P


The plants all seem healthy and are growing uniformly. It seems PlantA (with the top-dressed HGS) is growing slightly slower than the rest. I suspect this is due to a lack of O2 in the rhizosome from a combination of the HGS and the plastic pots.

Week Three

Day 15: Plants Receive Elite Nutrients and Enzymes Komplete

Day 16: Plants receive pure H20

Day 17: Plants receive Mammoth P

Days 18: Plants receive Elite Nutrients and Enzymes Komplete

Day 19: (Feb. 15) Plants receive CarboTerp with Enzymes Komplete in the morning a few hours prior to transplant.
-Transplant in the afternoon just prior to lights-off. Plants watered with Roots Gold post-transplant then left to rest in the dark.

PlantA (HGS on top of medium) has root growth, but less than the other three. One can see the HGS still toward the top 15% of the medium, indicating that HGS only leached down through a portion of the overall medium. I suspect the lack of rhizosomal growth is due to the roots’ lack of exposure to oxygen in the plastic pots. I am transplanting into 10 gallon fabric pots, which should supply more O2 to the roots, allowing for more growth. I will add a top dressing of the manufacturer’s recommendation of 1 part HGS to 3 parts coco medium.

PlantC has recieved no HGS

PlantB has the HGS mixed in the medium. Notice how the roots are well-developed. The HGS when integrated with the medium seems to provide the most vigorous root growth

PlantB (HGS mixed-in) is the plant to the right. PlantC (no HGS) is the plant on the left
Clearly, one can see the plant with the HGS mixed (PlantB) in has more robust root

Day 20: Dry day. PlantA and PlantB seem to be retaining more moisture today than are PlantC and PlantD.

Day 21: Plants receive Roots Gold. FIM tops. PlantA and PlantB are taking longer to fully saturate than are PlantC and PlantD. The HGS seems to be holding the runoff in the medium longer.

Week Four

Day 22: Plants receive Mammoth P

Day 23: Plants receive Elite Nutrients and Enzymes Komplete

Day 24: Plants receive Mammoth P

Day 25: (Feb 21) Plants receive Elite Nutrients with Enzymes Komplete

Day 26: Plants receive a light dose of Mammoth P.

Day 27: Plants receive Elite Nutrients with Enzymes Komplete

Day 28: Dry day. All plants are still saturated but PlantA and PlantB are the moistest


It seems the plants with the HGS (PlantA and PlantB) are in fact retaining more water in comparison with the control plants (PlantC and PlantD). The medium on the PlantA is visibly more saturated than the others. When I physically lift the fabric pot, I can feel the plants with the HGS are a bit heavier than those without the HGS (this additional weight may be due to the physical weight of the actual product, but also due to the water retention properties of the HGS). Growth rate appears to be comparable, however the main stalk on PlantB seems to be the strongest of all four plants in the study.


Day 29: (Feb. 25) Plants receive Elite Nutrients and Enzymes Komplete. Today the lights are flipped to 12/12 to induce flowering. Commence light pruning/FIM

Day 30: Plants receive Mammoth P

Day 31: Semi-Dry day. Plants receive a light watering of pure H20 and Enzymes Komplete

Day 32: (Feb. 28) Plants receive Elite Nutrients and Enzymes Komplete. Prune/FIM.


PlantA is definitely holding noticeably more moisture than the three other plants. PlantB is also holding more moisture than PlantC and PlantD, but less so than PlantA. As this study has thus far demonstrated, the manufacturer’s claim that the plants treated with the Harvest Gold Silica will retain more moisture than those plant without the HGS appears to be holding true. All plants seem to be equal in robust growth and overall vigor. The plants with the HGS also seem to have slightly stronger main stalks. Stand by for further results as we go into full flower.

Day 33: Dry day. Plants are all still visibly saturated (PlantA being the most moist)

Day 34: Plants receive Elite Nutrients and Enzymes Komplete. Prune lower canopy/FIM tops

Day 35: Plants receive a light water of Mammoth P. All plants were visibly praying this morning.

Day 36: (Mar. 4) Plants receive Elite Nutrients and Enzymes Komplete

Day 37: Plants receive Mammoth P

Day 38: Plants receive Elite Nutrients and Enzymes Komplete

Day 39: Plants receive Mammoth P


All the plants are all growing fairly uniformly. PlantA seemed to be a little slower than the rest of the plants, however as we close in on the two-week mark of bloom, PlantA seems to be catching up in both growth and vigor. The plants treated with the HGS seem to have shorter internodal spacing (i.e. less stretching) than do the control plants. As a grower, this is definitely what I’m looking for in my indoor plants. Flower set has started to show on all the plants. All the plants appear to be uptaking nutrients at similar rates, however the plants treated with the HGS still seem to holding more moisture than are the control plants.

Day 40: Plants receive Elite Nutrients and Enzymes Komplete

Day 41: Plants receive Mammoth P

Day 42: (Mar. 10) Plants receive Elite Nutrients and Enzymes Komplete

Day 43: Plants receive Mammoth P

Day 44: Plants receive Elite Nutrients and Enzymes Komplete

Day 45: Plants receive Mammoth P

Day 46: Plants receive Elite Nutrients and Enzymes Komplete

Day 47: Plants receive Mammoth P


After three weeks of flowering, all the plants are stacking nicely. It appears the plants that have received the Harvest Gold had shorter internodal spacing, but still grew an even canopy similar to the control plants that did not receive the HGS. I hope with the shorter internodes the dry harvest weight increases. Stay tuned for more flowering results.

Day 48: Plants receive Elite Nutrients and Enzymes Komplete

Day 49: Plants receive Mammoth P

Day 50: (Mar. 18) Plants receive Elite Nutrients and Enzymes Komplete

Day 51: Plants receive Mammoth P

Day 52: Plants receive Elite Nutrients and Enzymes Komplete

Day 53: Plants receive Mammoth P

Day 54: Plants receive Elite Nutrients and Enzyme Komplete


Following four weeks of flowering, I am seeing very positive results. The slightly shorter internodal spacing I observed in the plants with the HGS has definitely proven to be a benefit with the Lemon Betty cultivar. Lemon Betty’s sativa dominance genetically calls for stretching between the nodes. Any mitigation of this effect, however slight (even a centimeter), is a victory. The HGS has allowed for that victory. The overall health of the plants appears to be quite stable and similar in both the control and variable plants.

Day 55: Plants receive Mammoth P

Day 54: Plants receive Elite Nutrients and Enzyme Komplete

Day 55: Plants receive Mammoth P

Day 56: Plants receive Elite Nutrients and Enzyme Komplete

Day 57: (Mar. 27) Plants receive Mammoth P

Day 58: Plants receive Elite Nutrients and Enzyme Komplete

Day 59: Plants receive Mammoth P

Day 60: Plants receive Elite Nutrients and Enzymes Komplete

Day 61: Plants receive Mammoth P


5 weeks of flowering have passed since we first changed the photoperiod to 12/12. All the plants are growing well, but I am noticing the control plants (PlantC and PlantD) are experience a bit of chlorosis (yellowing of the leaves). I suspect the reason the plants treated with the Harvest Gold Silica are staying greener is the advanced bio-availability of micronutrients. The amorphous shape of the silicon molecule is retaining more moisture and thus making available more micronutrients to sustain the plants’ needs.

Day 62: (Apr. 1) Plants receive Elite Nutrients and Enzymes Komplete

Day 63: Plants receive Mammoth P

Day 64: Plants receive Elite Nutrients and Enzymes Komplete

Day 65: Plants receive Mammoth P

Day 66: Plants receive Elite Nutrients and Enzymes Komplete

Day 67: Plants receive Mammoth P

Day 68: Plants receive Elite Nutrients and Enzymes Komplete


We have closed 6 weeks of flowering now and the control plants (PlantC and PlantD) are definitely more yellow than the plants that were treated with the HGS. Lemon Betty is a cultivar that I have traditionally experienced issues with yellowing prematurely and I can comfortably say this product has helped mitigate that problem. The buds are all stacking nicely and are filling out quite well, The whole room has a pungent odor of fresh lemons…its delightful! I’ll be excited to see how the flowers finish up as we draw close to the end of this study.

Day 69: (Apr. 8) Plants receive Mammoth P

Day 70 Plants receive Elite Nutrients and Enzymes Komplete

Day 71: Plants receive Mammoth P

Day 72: Plants receive Elite Nutrients and Enzymes Komplete

Day 73: Plants receive Mammoth P

Day 74 Plants receive Elite Nutrients and Enzymes Komplete

Day 75: Plants receive Mammoth P

Day 76: Plants receive Elite Nutrients and Enzymes Komplete


After 7 weeks of flowering, the plants treated with the Harvest Gold Silica are definitely looking healthier than the control plants that received no silica. I don’t see much difference in overall weight (it is still early), but in terms of overall health, the plants with the HGS are still much greener and just healthier looking than are the control plants.

Day 77: (Apr. 16) Plants receive Mammoth P

Day 78: Plants receive Elite Nutrients and Enzymes Komplete

Day 79: Plants receive Mammoth P and Hi Brix molasses

Day 80: Plants receive Elite Nutrients and Enzymes Komplete

Day 81: Plants receive Mammoth P and Hi Brix molasses

Day 82: Plants receive Elite Nutrients and Enzymes Komplete

Day 83: Plants receive Mammoth P and Hi Brix molasses


Eight weeks have passed since we induced flowering in these Lemon Betty cuttings, and now we are closing in on the final phase of growth. Since Lemon Betty tends to be a 9-10 week cultivar, it’s safe to say that we will begin flushing sometime this week. The control plants are still exhibiting demonstrably more chlorosis than are the variable plants. Harvest Gold Silica definitely offers some serious bioavailability for my plants!

Day 84: (Apr. 23) Plants receive Elite Nutrients and Enzymes Komplete

Day 85: Plants receive Mammoth P and Hi Brix molasses

Day 86: Plants receive Elite Nutrients and Enzymes Komplete

Day 87: Plants receive Mammoth P and Hi Brix molasses. Flush Status

Day 88: Full 2 step flush

Day 89: Dry day

Day 90: Flush

Day 91 Flush


It’s the end of April and we’re coming to the end of this grow study. I have completed 9 weeks of flowering and the plants are looking - and smelling - quite lovely. The control plants yellowed out much faster than did the variable plants treated with the Harvest Gold Silica. Once I initiated the flush, I started to notice a bit of chlerosis (which is what I want, as this yellowing phenomenon indicates the plant is using up residual micronutrients) in the Harvest Gold plants, but not nearly as rapidly as the control plants. I also noticed that the Harvest Gold plants were better able to hold themselves up under the gathering weight of the filling flowers. The control plants all began to fall over this week. Clearly the cell walls in the Harvest Gold plants are stronger than the plants not treated with the silica and thus the Harvest Gold plants are able to support themselves.

Day 92: (May 1)Flush

Day 93 Flush

Day 94: Flush

Day 95 Flush

Day 96: Flush

Day 97 Dry Day

Day 98: Harvest in Dark

Two weeks of drying time were given between harvest and curing.


After the duration of the study some interesting facts came to light: the biggest and most glaring was the Harvest Gold plants actually yielded significantly LESS weight than the two control plants. I suspect this phenomenon may be due to to the top dressing choking out the roots of PlantA and restricting oxygen. Interesting and surprising results, to say the least. I would definitely need to study this product further before recommending it to any other growers. I wonder about the residual silica in the finished flowers, especially given the amorphous shape of the silica molecule and the fact that it cannot be flushed from the medium.

All things considered, the plants all grew vigorously and produced a decent yield.

The final weights of the plants (below):

  • PlantA: 88 grams
  • PlantB: 116 grams
  • PlantC: 149 grams
  • PlantD: 152 grams

This marks the culmination of the study. What are your thoughts, GNET?


This is going to be awesome! @mastergrowers


Are you weighing the amount of water each plant receives? Watering by hand? If microbes need to break the silica down then it will be a neat comparison with the top dress as that will be dry most of the time.
I noticed with multiple top dresses (one watering to settle) while still bottom watering in general, prepared the top of soil for flower without over applying all at once. And it had hardly broken down at all.
Once top watering started regularly the top dress was gone in a couple weeks.

Do you just straight water molasses? Have you thought about priming an aerated tea (with microbes, then feed them molasses and then water that into the pot after 24-36 hours?
Small amount of alfalfa pellets has lots of enzymes and nutrients as well. (Especially as a foliar. That will green them up as well as give them some defense against powdery mildew potentials)
This would make the molasses available to the microbes quicker and this the plant could uptake the nutrients quicker.

I made a aerated compost tea with blended cucumber and diatomaceous earth and watered that in.
I have a theory it may work as well. Heard there is a lot of silica in cucumber. And in DE.

May run a trial on that in the future. So I’m curious what this product will do as well.
Came up a lot at the conference as well. It’s amazing now that the professional industry is meeting the “stoner science”.

I’m just finishing weighing a set of 4 for the last few months once beginning every “lights on” day. It’s actually amazing to follow the individual plants needs.
It’s really neat to see that if conditions don’t change too much there’s almost identical numbers used/transpired. (Per plant. Each plant really is very different but still acts on her own schedule. Hope to input that data into graphs and such yet this winter then will share.

(Got idea from conference last fall. He suggested weighing seedling flats. It’s very important during that stage to allow proper dry time one the radicle had emerged, veg was also super important to allow dry wet cycling (level 2-4 not 1-5 for example)
Even while in flower, there was a surprising bonus to yield. (Trial was in coco using nutes, advanced nutrient or general hydro I believe at university of Guelph)


Awesome good to know. I was aware of some of those features of alfalfa. It’s new to me. In terms of your molasses I would add that as soon as the ingredients went into the tea.
Unless you make heavily amended teas (like in TLO by the rev). Which IMO aren’t aerated compost teas as much as aerated nutrient water. And depending on the primer may not actually activate too many of the ingredients beyond moisture. (They need to be eaten by bacteria that then are consumed by I think Protozoa and Arthropoda and that’s how those chemicals are released for the plants. )
And simple teas are best for mass diversity of microbes. The molasses usually needs at least 8 hours to be used up I’ve heard.
Don’t quote me on that. Or anything for that matter. ;). Just reasons to explore, right.

Check out Tad Hussey ( on YouTube. he has some footage of his microscope analysis of microbiology increase in various tea ingredients.

The cucumber having silica I heard from a nutritionist for us, and also someone talking about worm compositing once, I like to think out of the box and try things.
There are enough plant teas as well as sprouted seed teas that are effective.
I use fresh blended aloe in the AACT as well as a surfactant during foliar applications. Aloe also gives enzymes/benefits towards heat stress.

Diatom earth is considered a soil additive in living soil for silica and can be used to control certain insect pests.

In terms of weighing the plants yes. Such a pain in the behind. Especially with my new injury. But I figure, and from what I’m seeing if you start with weighed ingredients during potting and then do mostly everything the same every run for example. It will be a good way to improve your current judgment on the watering scale.

My current run isn’t quite finished. Couple weeks out yet. Nor will I have a direct comparison. The study that I got the idea from (university of Guelph) had massive improved yields. Up to 20%.
Dry time during veg was hugely important. Then less during flower. But still added some benefit.
They noted cannabis doesn’t care and yields very well grown in any reasonable condition. And only trialed coco and nutes. Two types of coco mixes.

I’ve always grown on the dry side. In nursery or vegetable production. I have always had better results. Whether that is because it matches the way I want to grow or maybe it’s better. Not sure.
In living soil most people grow in “swampier” conditions for the microbes to be most effective and not due, then have all sorts of problems.
I’d rather replace the microbes than the ladies were growing or the flowers I’d be missing. ;).

The weighing came from a talk on seedling germination and young plant development health.
If you think about those first moment of life and many facilities have lacking propagation areas. Ok veg and nice flowering area.
Why not have a really good propagation area to give them the best start possible?
(less disease pressure from start, faster transfer into vegetative growth etc)
And then there’s the chance at better yield.

He suggested weighing entire flats to avoid over watering.
This is all very beneficial if you have to train others to water in your facility.
As a grower you know when and why you do things. When you say to someone new “watering is a science and hugely important” people look at you strange.

The amount of instructional videos and such I see that people dump water on soil. Or fill a pot to water it. Very sad.
So this is a useful technique to get into.

But yes a lot of labor. Which I believe could be easily incorporated and rechecked every few cycles. Or if the industry pricing holds one can developed pots or rolling tables with self weighing features. That will add to a watering system such as blue mats.
Timed watering will not be as effective as watering by hand for example.
So it’s a closer automation to human watering intuition.


The plants are looking great @Growernick! Thanks for the update on the progress! @Joella_HGS


Look at those roots!

Looking great @Growernick, love the journal so far!


Indeed. I have two cents to throw in here. And take it with a grain of salt. But let’s figure this out.

IMO this is improper saturation of the medium during watering. Ie one plant is dry and one is not. Both are watered at same time. This is what happens.

Back to the reason why I weigh my plants. One can make sure that not only the plant has dried suffiently but also that one has saturated it properly writhing set scale as well.

This swing in wet dry is what forces roots down to bottom of pot.
Also if I may. Rooting happens in dark yes, rooting happens much less when watered. So watering and then allowing dark time is in fact causing aenarobic conditions as the is very limited evapotranspirstion as compared to lights on.
This will give an increased chance in root diseases and allows the anaerobes to dominate within th rhizoshphere. As the aerobes have a difficult time surging without oxygen.
Water before lights on.
You could still repot and dark time (no water)
They will root in dark (proven with 18/6 :24hr comparison study by UOG. But they can’t have wet feet because then they are not rooting. Especially during transplant shock.

Add myco (in still trailing myco) and plant. Water in. (I repot a drier plant and then water entire thing. Which equalized the water from the drier oeatmoss/coir to the wetter.

That’s why the roots bunch at the top. There is the oxygen or they didn’t dig because it was too wet below. U can see the brown roots in bottom which shows they’re was either root death or drying.

I’ve been playing with watering cycles for many years in many crops. It’s hugely important. I attend a lot of conferences for science results)

Interesting trial thus far. Great job and awesome write up! :+1: Will be cool to follow along.


Wow, They look healthy!


Thanks for all the valuable info! I definitely see the advantages to weighing your plants pre- and post-watering; however, in my experience as a commercial grower, unless there are some serious industrial improvements to accommodate mass-weighing of plants (say, in 4x8 flood trays with large scales, for instance), it’s difficult for one to weigh individual plants (far beyond the infrastructural constraints of my grow lab). Also, the labor costs of weighing individual plants at an industrial agricultural level far outweigh the inherent benefits. On the flip-side, for research purposes, your suggestion would offer loads of valuable, quantitative data. What I am trying to accomplish is a study which can be scaled for industrial applications, as well as demonstrate the efficacy of the product. Also, I want any grower to be able approach the data and be able and easily replicate my results.

With that in mind, I am watering the same quantity of nutrient solution to each plant to reduce the total number of variables in the study to just the control and variable groups. Every plant receives equal nutrients in equal quantities every day. I am observing and documenting the results accordingly and measuring the growth rates through observation and presenting the data to all the members here at GNET.

That being said, I agree with the info that you have provided, and furthermore, find it very valuable and interesting (and precisely the kind of dialogue I wanted to create, so a big THANK YOU!!). Agreed, rooting happens in the dark and an overly saturated medium creates an anaerobic environment inhospitable for rhizosomal production (thereby opening the door for pathogenic, bacterial, and root-killing insects to thrive). My sincere hope is the organic, microbe-rich rhizosome ought to help combat many potential issues before they bear their ugly heads. Also, a quick-drying medium helps thwart many issues in advance.

I always water right before lights-on, just as you suggest (for all the same reasons) and allow the mycorhizzae to do its magic post-transplant. I find it’s a judgement call on the moisture content when transplanting: certainly an overly-saturated medium risks falling apart when the plant comes out of the pot. Alternatively, trying to transplant an overly dry root mass can also result in medium falling apart and root damage (not to mention leave a huge mess of coco, perlite and detritus!). So, for me, transplanting is a matter of finding a healthy balance of wet to dry.

Having done a little growing in my time, I also find it’s a lifelong journey to discover the proper watering cycles, timing and ratios, but it seems like we have both come to similar conclusions.

Again, thank you for all the info and data (and compliment :sunglasses:). Let’s keep this growing!


Plants are looking good @Growernick! Love the grow journal!


how can Rkag do performance test


Hey @ralpht,

Please send me a direct message if you (or anyone else) is interested in performance testing.


I have two new materials that I would like to test as silica based. both carbon organic sources. Silicon is a great benefit to plants

1 Like

Hey @sjoerdvisser!

I am watering by hand a similar amount of water/fertilizer to each plant. I am allowing for about 10% runoff in each plant. I will note when individual plants need different feeding amounts (as I anticipate will happen with the application of the silica). As you mentioned I also have noticed the top dress or HGS starts to leach down into the media in PlantA with every watering. I will re-apply an additional top dress of HGS immediately post-transplant when I move into the 10 gal fabric pots in which I intend to flower.

On the topic of molasses: I aerate a solution of high brix molasses for about an hour before applying to the plants. Sometimes I will make a compost tea or a microbe brew and then, yes, I will add the molasses toward the end of the brew to as a catalyst to activate the microbial life. I like alfalfa for a number of reasons. Not only is alfalfa rich in enzymes, medicago sativa contains a decent quantity of triacontanol, which stimulates a stress activated response in our plants, increasing essential oil and resin production. This action results in a stronger finished product!

I have never heard of using cucumber and DE as a source of Si, but I would love to try out your brew recipe! Thanks for the tip!

I’ll keep updating this study at least weekly and let people know if this is a product I would recommend. I usually recommend products that produce meaningful results and I would use over and over again. So far I am seeing only a slight difference in growth rates between the control and variable groups, but we are still early in the study…

I’ll have to try weighing plant in the future…seems like a lot of labor but it sounds like you are getting meaningful results by doing it. How much was your dry yield increased by integrating weighing into your cultivation practice?