High Light efficiency tests (TEKNIK) - 2.47 umol/j CRI 94.2

PSUAGRO. said:

This debate is as old as the forums........but yes, plants will "self-defoliate". with high RH (in full flower) I find it beneficial to leaf strip to avoid fungal issues, not for increasing yields IMO. Granted this all comes from my outdoor practices/schooling and doesn't always translate well to indoor : ) your YMMV

Happy growing

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I strip away probably 80% of my leaves.

I do this to avoid fungal issues. lots of leaves = a small micro environment where RH is 99%. That is not good and will only harm the plant.

A stretchy Sativa I wouldnt prune. My plants are short indica's.

Porky101 said:

I strip away probably 80% of my leaves.

I do this to avoid fungal issues. lots of leaves = a small micro environment where RH is 99%. That is not good and will only harm the plant.

A stretchy Sativa I wouldnt prune. My plants are short indica's.

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That is a fair point. Horse for courses and all. I stripped down some indicas more than I normally do this grow and still got a bit of mold I had lots of air blowing through there, too, but it's been wet and these were test seeds that grew pretty solid buds.

Porky101 said:

I strip away probably 80% of my leaves.

I do this to avoid fungal issues. lots of leaves = a small micro environment where RH is 99%. That is not good and will only harm the plant.

A stretchy Sativa I wouldnt prune. My plants are short indica's.

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Prawn Connery said:

That is a fair point. Horse for courses and all. I stripped down some indicas more than I normally do this grow and still got a bit of mold I had lots of air blowing through there, too, but it's been wet and these were test seeds that grew pretty solid buds.

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In the end, just do the best you can to get a clean/safe finished product.......thats all you can ask for.

PSUAGRO. said:

In the end, just do the best you can to get a clean/safe end product.......thats all you can ask for.

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I find it is a balancing act. Stripping away leaves will lead to yield loss. Less leaves = less evaporation = less nutrient uptake = less final end plant biomass.


Lets say you had a sealed, sanitised room. With zero spores. Hepa filters everywhere with UV as additional sterilisation.

You could probably grow a plant that is incredible stacked and not worry about fungal disease. Aslong as you have lots of wind replacing the CO2 for the plant, that would probably ensure maximum yields...

Porky101 said:

I find it is a balancing act. Stripping away leaves will lead to yield loss. Less leaves = less evaporation = less nutrient uptake = less final end plant biomass.


Lets say you had a sealed, sanitised room. With zero spores. Hepa filters everywhere with UV as additional sterilisation.

You could probably grow a plant that is incredible stacked and not worry about fungal disease. Aslong as you have lots of wind replacing the CO2 for the plant, that would probably ensure maximum yields...

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Sure, dialing it in is a balancing act........lose a crop to fungal, and its definitely noteworthy; fear carry's on. Hence why systemics are so popular.

UVc treatments aren't very effective and need a certain exposure to destroy, UVa&b do nothing generally speaking.

Edit. Don't get me wrong crop protection products absolutely have their place, just need very careful consideration on something you inhale.

I think there's something wrong in my grow if I don't have a little bit of bud rot......

Moflow said:

I think there's something wrong in my grow if I don't have a little bit of bud rot......

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Haha! I know what you mean - it usually comes with dense buds.

PSUAGRO. said:

Sure, dialing it in is a balancing act........lose a crop to fungal, and its definitely noteworthy; fear carry's on. Hence why systemics are so popular.

UVc treatments aren't very effective and need a certain exposure to destroy, UVa&b do nothing generally speaking.

Edit. Don't get me wrong crop protection products absolutely have their place, just need very careful consideration on something you inhale.

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Yep I hear you. I use zero chemicals in my grow (My nutrients are chemical ferts though). . through veg and flower. Everything is organic pest control wise. I use a killer fungus to fight my other fungi attacking my plants. (fungi will fight eachother for resources the fungi I use doesent attack my plants atall). I use co2 to kill insects.


I have noticed decreased amount of spore counts under area's with CMH. I use a handheld TVOC meter to analyse air quality.

My biggest challenge is airflow through the leaves, even if your room is fully sanitised, if you have dense plants, your co2 exchange on the packed sites will be less and RH will lead to very slow growth around those areas, robbing the tops of growth.

The more I think of it, there is no way around defoliating a dense plant. Sativa's are lanky so they probably wont need as much defoliation.

Newest research suggests that light from UVC to the blue range is able to kill insects. Like UVA destroys dna blue light has damaging effects on the protein production and kills insects this way.
UVB kills also spores and fungi it only takes longer. UVC works for desinfecting surfaces but its dangerous cuz you need to repeat the treatments every few days and its easy to damage the plants as well. I've used my UVC handheld only in the last few weeks for my greenhouse plants cuz it gets wet here in october. I've also use 2 inch long pieces of drinking straws to put them inside the biggest buds to allow eventual water to evaporate faster.

Fact is since I'm using UVB/A reptile bulbs I've neither seens any insects nor any fungal infects, no but rot, no PM, nothing and I usually keep the humidity pretty high to keep the VPD where I want it.

Most of the time bud rot aprears when there is condensed water inside the buds which can not evaporate. Its weakening the cell walls. No condensed water, no bud rot. Dew point and night temps play a big role and often it helps to use a small heater at night to keep the ambient temps above the dewpoint.

There are other things we can do to help our plants to stay healthy.

Using a silica product helps to strengthen the cell walls so its a good way to help your plant to fight against fungal infects. ASS(yeah, I mean acetylsalicyl acid) is also helpful cuz it suggests the plant its attacked by insects or fungus. She puts more effort in self protection and cuz there was no real attack the is better protected.
Simply dilute an uncoated 500mg pill in a gal. of water and spray it on the leaves(every 2nd week until bloom week 2). It has other beneficial effects from improving nutrient content in fruits to make them more resistant and most tomato growers here use the technique to get better and more fruits.

BTW, I fully agree with PC
Fastest and most productive growstyle is a SOG using 25 cuts per squaremeter. With an 8 week hybrid you can have up to 6 runs per year with no veg and have still time for holidays. Truth is as soon as you start to give them some additional time to veg you'll lose yield.
Coco slabs or rockwoll cubes helps a lot to reduce the additional work. The rooted clones go directly in the rockwoll cubes and with an ebb 'n flow system its really not much more work. Even if you use coco slabs and drippers it don't takes longer.
There is simply no other way to harvest 6 times per year and even if you yield slightly more with additional veg you can not compensate that.

I see plenty of botrytis, PM, etc. On leaves/plants in FULL sunlight with high UVa, b.........just saying, hence my opinion on the matter. Indoor might have different "effects"? Idk, nutrition/genetics/environment could impact these findings as well....

PSUAGRO. said:

I see plenty of botrytis, PM, etc. On leaves/plants in FULL sunlight with high UVa, b.........just saying, hence my opinion on the matter. Indoor might have different "effects"? Idk, nutrition/genetics/environment could impact these findings as well....

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Yeah, insects sit usually on the bottom side of the leaves to avoid getting touched by strong sun light. Indoors they do the same, most of them incl. their eggs are on the bottom side. With their faceted eyes they can see into the UV range and they avoid getting in contact with it. But to be honest, I'm using DE(1cup/3gal) and neem cake(½cup/3gal) at least in soil so insects are pretty rare in my groom anyways.

Most of the time fungal infection occurs in fall when the suns intensity is much lower. Pretty sure there is no PM or bud rot in high summer when the conditions are relatively dry. Spores are almost everywhere out- and indoors and plants "collect" them all the time and as soon as its gets colder and the spores find good conditions(wet enviroment, temps below 20°C, weaker cell walls or damaged leaves) bam! For outdoors I would recommend to use strains with a known natural resistance. Hollands hope for instance is an old outdoor strain developed for growers living above the 50th degree of latitude and has a natural resistance against pm and other fungal infects ... but only up to a certain point. When cell walls gets weaker it always opens the door and if there are spores the infection will happen either way.
Indoors we remove damaged or wilting leaves as soon as we see them, we lollipop to allow a better air flow and we prune off unwanted leaves. All this helps to keep the humidity lower and make it harder for spores to infect the plants.
If you use UVB every day for up to 6h new spores gets killed pretty fast as soon as they come in. I start using it a week before I see the first flowers. If used only in the last 2 weeks there are already spores deep inside the buds and there is no way to destroy them cause the buds are already too dense. In such a case UV light would have no effect.
Most growers also keep their groom clean and desinfect tents between two runs. Outdoors infected leaves lie practically everywhere on the ground. So the probability of an infection is much higher.
Pretty sure there are more reason which I did not think of.
When I grow outdoors I'm using only automatics now and plant rather a few more plants. Regular strains start flowering later in summer and you need to wait at least until end of september. With auto's I can use the hottest two or three month of the summer for the flowering stage and can harvest in august or earlier. IMO, that's the best way to avoid issues with fungal infections.

PC, here ya go at 4.5 weeks

Beautiful mate! They're healthy as fuck! But I know it will never make up for what happened in the cricket - I watched the whole game

Well far from optimal conditions - day temp 68, night 41 so putting em to the test. EC2.2, still adding tsp epsom to 3 gallons.

Fair play to England they took their chances and we fought hard so great game!

Frank Cannon said:

PC, here ya go at 4.5 weeks
View attachment 4365806

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Looking fantastic Cannon, i hope they smoke like one

Frank Cannon said:

Well far from optimal conditions - day temp 68, night 41 so putting em to the test. EC2.2, still adding tsp epsom to 3 gallons.

Fair play to England they took their chances and we fought hard so great game!

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Smashing temperatures mate. Lol
You'll have no problems hopefully, my temps are similar in winter.
Its Summer here now and plants in flower are getting a tropical 31°C - 87f max lights on and they're loving it!

Yeah its funny, I have had less probs this grow with nutes and at these cold temps in the wintery Southern Alps than summer so prob VPD related in summer, if I pull 2/3rds what the the QB96s got in summer conditions I will be a very happy chappy! Shit even a third would still be on a par with my 600HPS

Frank Cannon said:

Yeah its funny, I have had less probs this grow with nutes and at these cold temps in the wintery Southern Alps than summer so prob VPD related in summer

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C'mon mate, you know it's the lights

Frank Cannon said:

if I pull 2/3rds what the the QB96s got in summer conditions I will be a very happy chappy! Shit even a third would still be on a par with my 600HPS

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Well you might be happy, but I won't be! Watt for watt, I'm expecting these to equal or better the QBs.

One thing I have noticed now that I'm harvesting my first full grow under them is that the trichome build-up is phenomenal. I have one of my usual strains to try soon, so that will tell me whether the smoke is any better/stronger. Totally subjective, of course, but going by the smell and trichs, I expect good things.

I know mate, but they are hardly getting optimal grow conditions currently so I would have expected yield to drop off ....

Don't worry mate come spring I'll let you know about performance

BTW, I just checked your combined 2700K + UV reptile bulb spectrum again and saw it was CRI96 - close to true colour.