Recommended light intensity for autoflowers fluence spydr 2i 630w led

DoubleD5374

Well-Known Member
I’m curious as to how high I should run my led light for autoflowers . I had extremely short , bleached small bud autos this grow - and I believe it’s because I had my lights way to high. My dimmer adjusts from 0-100% and has pulled 2.5 lbs off photoperiod plants in a 4x4 tent.

I’m growing in autopot. Xxl system 9 gallon , with canna coco nutrient line , in 50/50 coco perlite .

I believe I absolutely caused more harm than good , with this light .

I’m open to any suggestions on intensity for seedling stage , veg stage as well as flowering stages early mid late .

These are not small because of genetics - and the 9 gallon pot is 100% full of roots - I think I kept the light to low / to high .
 

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joesoap2013

Well-Known Member
I've only grown photos
Your dli would be way higher if you were using the same light intensities as photos
Seedling low I've the ppfd app it mighten be accurate but when it's 300 I know it's OK
Start of veg end of veg bes different start same as seedling then work your way up a 100 or 200 to out 450 umols by the end of veg maybe even more if you can get away with it 500 maybe
 

DoubleD5374

Well-Known Member
Im gonna get a par meter I believe and do some research onto what autos prefer . I’m not sure if there’s a decent option out there for relatively cheaper than the 250-300 dollar prices I’ve seen ?
 

1212ham

Well-Known Member
Im gonna get a par meter I believe and do some research onto what autos prefer . I’m not sure if there’s a decent option out there for relatively cheaper than the 250-300 dollar prices I’ve seen ?
If you have android I suggest the $35 uni-t bluetooth Lux meter paired with the ppfd meter app. Do a search here for uni-t and you will find many posts.

For iphone you can use the photone app. It uses a phones light sensor so accuracy will depend on the particular phone used.
 

Rocket Soul

Well-Known Member
My advice is to adopt a babying approach to start with, around 10-15w per square foot and then slowly turn it up and look for usual signs of unhappy plant.

Its tricky to give direct advice, each plant is its own universe.

The one thing to factor in is your light cycle: if your 24hrs on at max your effectively giving twice the light in total per day you would give to a photoperiod. Its not the intensity that give problems more so the accumulated light given per day.

Light measuring (doesnt have to be par meter, lux is ok for white leds) and checking ec of runoff. But now that i remember your in autopots so no way for this. Personally i dont like them for leds.
 

cat shit

Active Member
I’m curious as to how high I should run my led light for autoflowers . I had extremely short , bleached small bud autos this grow - and I believe it’s because I had my lights way to high. My dimmer adjusts from 0-100% and has pulled 2.5 lbs off photoperiod plants in a 4x4 tent.

I’m growing in autopot. Xxl system 9 gallon , with canna coco nutrient line , in 50/50 coco perlite .

I believe I absolutely caused more harm than good , with this light .

I’m open to any suggestions on intensity for seedling stage , veg stage as well as flowering stages early mid late .

These are not small because of genetics - and the 9 gallon pot is 100% full of roots - I think I kept the light to low / to high I start my autos under a t5 for about a week at 150 ppfd then they'll go under a led at 200ppfd from there I'll up the dimmer every few days and see how they react constantly upping ppfd through veg to get to a dli of 40 to 45. My Max at veg is 300 to 400 ppfd then as soon as they can handle it around 700 to 750 ppfd. I use a lux meter and watch how the plants react to every change in light intensity you'll soon k oe when they are getting to much at 18/6 the requirement is a fair bit less than photoperiods. In saying that they are just the same they love as much light as you can provide.
 

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Rocket Soul

Well-Known Member
Tbh i dont see too much problems with those pics. On pic 4: front plants look like its about to finish (right) or maybe a bot hungry (left).
In our grow we generally like our plants to look like the front 2 if theyre about to finish, means that the plant is cannibalizing which is good towards the end; you want the chlorophyll to fade a bit. Though it depends if you feel flush being necessary or not. To me plants that dont fade tend to get a sharp taste of nutes/unwashed roots.
 

cat shit

Active Member
Tbh i dont see too much problems with those pics. On pic 4: front plants look like its about to finish (right) or maybe a bot hungry (left).
In our grow we generally like our plants to look like the front 2 if theyre about to finish, means that the plant is cannibalizing which is good towards the end; you want the chlorophyll to fade a bit. Though it depends if you feel flush being necessary or not. To me plants that dont fade tend to get a sharp taste of nutes/unwashed roots.
Oops those pics are mine I was giving OP some ppfd advice with pics. Yes the front 2 are 13 weeks and back 2 are 9 weeks the leaves never look that good just before harvest I loke all the different colours
 

cat shit

Active Member
I’m curious as to how high I should run my led light for autoflowers . I had extremely short , bleached small bud autos this grow - and I believe it’s because I had my lights way to high. My dimmer adjusts from 0-100% and has pulled 2.5 lbs off photoperiod plants in a 4x4 tent.

I’m growing in autopot. Xxl system 9 gallon , with canna coco nutrient line , in 50/50 coco perlite .

I believe I absolutely caused more harm than good , with this light .

I’m open to any suggestions on intensity for seedling stage , veg stage as well as flowering stages early mid late .

These are not small because of genetics - and the 9 gallon pot is 100% full of roots - I think I kept the light to low / to high .
Sorry OP my pics were for you to show progression of plants with increasing ppfd aggressively as they grow there is plenty of info out there on autos good luck
 

cat shit

Active Member
Tbh i dont see too much problems with those pics. On pic 4: front plants look like its about to finish (right) or maybe a bot hungry (left).
In our grow we generally like our plants to look like the front 2 if theyre about to finish, means that the plant is cannibalizing which is good towards the end; you want the chlorophyll to fade a bit. Though it depends if you feel flush being necessary or not. To me plants that dont fade tend to get a sharp taste of nutes/unwashed roots.
Yes I never flush and feed till the end they always fade hard as they should
 

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DoubleD5374

Well-Known Member
Tbh i dont see too much problems with those pics. On pic 4: front plants look like its about to finish (right) or maybe a bot hungry (left).
In our grow we generally like our plants to look like the front 2 if theyre about to finish, means that the plant is cannibalizing which is good towards the end; you want the chlorophyll to fade a bit. Though it depends if you feel flush being necessary or not. To me plants that dont fade tend to get a sharp taste of nutes/unwashed roots.
I was more concerned with the size , more so than anything .

I had a deficiency issue/ light issue in weeks 3-5 and it really slowed the growth down , and bushed heavily .

im used to growing monster photo plants , and after seeing mega yields everywhere online with the same setup /genetics , canna coco , and autopot - I was expecting way more .

I know somewhere along the lines I messed up. I just don’t know what caused it - so I’m trying to dial my lighting in first , and get a good plan for feeding on my next round , so I can do the genetics justice .

on a side note - the flower is done drying and ready to be cured , and quality is definitely not an issue whatsoever . “Picture was at least 10-15 days ago “ and wasn’t taken the day I posted . It’s been drying for 10 days now .

I couldn’t resist a taster , and I’m glad I didn’t because even without a cure it’s extremely tasty , not harsh at all , and extemely potent.

I’m gonna run it through the T check next week - and see what we’re looking at , but it’s as strong as my outdoor greasy runtz this year, which hit 25.5% on the same device yesterday “also had 2 weeks to cure”





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Rocket Soul

Well-Known Member
Im getting confused about the pics of Cat shit, lol.

Basicly:
- trying to ask peeps online "how much light can i give to my plants" is probably not the best idea. Each plant is a universe of its own and how will we know better than the plant? Also the amount of light you can give depends on so many factors as temps, rh, nutes, previous adverse conditions etc - you need to "ask" the plants themselves by learning how to read them.
Start on low power; and factor in that longer hours of light means more total light. Up slowly, if you have to do it by steps: go up one step for a day only and then next turn it back down, see how they handle a day and evaluate.

Autos will not grow as big as photos; they have a much shorter veg period. For bugger autos go for + 90 days. Make sure you dont f up in the start cause it will mess with everything after.
Once youve burnt your plants with too much led light they will act very bad like forever and never really man up.
Hope it helps
 

Delps8

Well-Known Member
I've grown autos and photos. I don't grow autos any more because I found they grow too large. I grow in a 2' x 4' x 8' tent and, since I can't flip them into flower, which stops their vegetative growth, they end up growing very tall. With photos, I can flip them at day 40± and that allows me to keep them smaller.

Two Gelato autos. These ones were pretty well behaved but I had to use my Vipar XS 1500 to light the "front row" of one of the plants.

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Nice compact photo. 30" across, 20" front to back, and about 24" tall.

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Light levels - autoflower cannabsi plants are cannabis plants, usually hydrbrids of cannabis indica and cannabis sativa, that have some genes from cannabis ruderalis which allows the plant to not need to be flipped go into flower. Astute readers will note that all of the plants are "cannabis" and they respond very similarly to light. Cannabis is a light whore loves light.

I grow all of my plants at >1kµmol because there's a direct, almost linear, relationship between the amount a cannabis plant receives and crop yield. One researcher found that there's roughly a 4.5% increase in yield for every 50µmol above 600µmol that the crop receives. I created the table below from the paper, which is cited.

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In Mitch Westmoreland's YouTube videos from earlier this year, he discusses yield, among many other excellent topics, and states that the amount of flower yielded in a cannabis plant is 0.2 to 0.3 gm/sq meter/mol. As the plant gets more light, it will be able to photosynthesize more which allows it to generate more glucose which allows it to grow more. I liken it to pressing down on an accelerator pedal in a car. The engine will run faster, up to a certain point. In an engine, it's the red line; in a plant, it's the "light saturation point". When growing autos, I hit the LSP at around 1kµmol but for my two photo grows, the LSP was 1100µmol±.

The difference between plants of the same strain should not be significant. The LSP is "800 to 1000µmols" but I've not done a grow that tops out at 800. Since I've only done 6 or 8 grows, that's not surprising but you might run into a strain that can't handle more than 800. So be it.

A big point to remember is that the PPFD for one spot not the canopy may well be 100µmol different that a location just a few inches away because a canopy is not perfectly flat and even the best lights don't have a perfectly flat PPFD map. That's why you can get a plant to, say, 1kµmol in some places but, in others, it will be 900 and 1050. And then you'll take a light reading in 5 minutes and that 1k spot is now reading 960 because you're holding the sensor 1" away from and 1" below the original spot.

Lighting on a canopy is "an area weapon", so to speak.

PAR meter? If you've got $300 burning a hole in your pocket, check out the Spot On PAR meter. Shane sells it and, while I have reservations about the light output of his lights (his drivers tend to be lower wattage than his competitors which is why his lights don't generate PPFD's in the 1k range) he seems to be a good company to do business with.

I use an Apogee and have a Uni-T lux meter. Unless you have to have an "unimpeachable" source for your PPFD readings, you can get close enough with a lux meter and a conversion factor. I've attached a document I wrote that will help with the conversion factor issue. In most cases, 0.015 is a good number.

Whether it's a PAR meter or a lux meter, the meter will just tell you how much light is falling on a plant but the plant will tell you how much light it can use. Those are, usually, not the same. The advantage of a PAR meter is that it makes it easy to sample a canopy and record the data. This is how I record PPFD for a canopy in veg.

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With the data in a grid pattern like that I can add plant hangers to even out the canopy.

Re. DLI for autos - I've grown mine at 70-80 mols but photos only up to about 42, IIRC. Yup, 80. For the auto in the picture above, I think I turned the light down to 850±µmol for the last few weeks of the grow. One reason was that the tent was getting pretty warm. Second reason was that there was so much weed in there that it just didn't make a difference.

Yeh, the big plant was Chris (Evert) and Wilma (Rudolph). The latter name was because the seedling was a lot smaller than the other one.

IMG_7497.jpeg


Re. bleaching a plant with an LED — Bugbee talks about flowers that are bleached. Bleached colas aren't, per se, a problem but they look strange. He's found that flowers get bleached under high amounts of light when the lights that are being used have very high amounts of red. I use a Growcraft flower light at PPFD's and haven't see that but there are other lights out there are have a higher % of red.

Re. giving a plant so much light with an LED that it damages the plant. That's not easy to do. I end up giving my plants too much light almost every grow but the plants respond very quickly (canoeing/tacoing or rotating the leaf around its petiole like a Venetian blind) so I turn the wattage down a bit or raise it an inch. The only permanent change I've caused was that one large cola bent at the top and never straightened back out. Other than that if you set a new light level, check on the plants in 30 or 60 minutes and then an hour later and see how they're doing. If they're reacting negatively, just reduce the light level a bit and they should return to normal.

How quick to ramp up? There's no reason to gradually increase, not as far as the plant is concerned. Light is how plants make food. Feed your plants well.

In one of his video interviews, I think it was Mr GrowIt who asked Bugbee that question. There were two parts to the answer. In terms of mimicking the sunrise, there's no value in that. "Cannabis is ready to go to work as soon as it gets out of bed in the morning"- that's not an exact quote but it's really close. What Bugbee didn't say in that interview but he has published elsewhere is that, while cannabis is ready to "go to work", it takes a few minutes for photosynthesis to ramp up, so light schedules that alternate short periods of light and dark aren't quite 100% efficient because of the ramp up time.

The other issue was about taking a plant from 600µmol to 1000µmol. Per Dr. B, that's something that you should be able to do in two days. The key point is to watch the plant and see how it reacts. It's really hard to harm a cannabis plant with too much light from an LED. Sure, if you turn it uo to 11 and go away for the weekend, that's not too a good idea but if a cannabis plant is at a modest light level and you add 200 µmol, you should be in good shape. If not, go through the checklist and figure out why.

The only time I've seen plants not be able to handle 800-1000µmol was due to poor watering practices. In both cases, the growers had hygrophobic soil. With those being the exceptions, you should be able to get a grow to at least 800µmol. If not, the diagram below can help troubleshoot.

10 Parameters of Growth.png
 

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Fladawg01

Member
I run my Vivosun VSFL4300 at 80% right now as my girls are in flower (4th & 5th week) I cannot go to 100 due to temps in my 4X4X80 getting way up above 82 degrees. When they were in Veg I ran them at 70%. It's the distance away that will raise the PAR. Ib flower I am 18" in veg I was 24" roughly. I use a separate baby grow light when seedlings are on 2nd leaves, then transfer under my main light at 60% and 30 inches away.
 

Rocket Soul

Well-Known Member
You can flower led plants at 82F, its actually more or less recommend to keep temps around there. With no infrared heating the leaf the 79F ceiling for temps usually recommended for hps becomes the floor for high intensity led light grows. Of course you still need to keep and eye on your plants for possible heat stress but its not impossible by any meams to run your flower around those temps
 

Delps8

Well-Known Member
You can flower led plants at 82F, its actually more or less recommend to keep temps around there. With no infrared heating the leaf the 79F ceiling for temps usually recommended for hps becomes the floor for high intensity led light grows. Of course you still need to keep and eye on your plants for possible heat stress but its not impossible by any meams to run your flower around those temps
A few years ago, Mitch Westmoreland did a study on the impact of temperature on flowering cannabis. That research was part of his work for his PhD and he released a new, much more comprehensive video early this year in which he touches on a variety of topics re. cannabis.

In sum, he recommends letting temps rise to 85° in veg and for the first two weeks, or so, of flower. The reason for this is to maximize the build out of the plant. As of the second week in flower, which is when build out stops, the temps of the tops of the flowers should not exceed 78° in order to preserve cannabanoids. That 78° mark is the maximum and some strains should be even lower.

This is a screenshot from his video.

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This is one of two videos that have very similar content. They're superb and I would recommend that every cannabis grower watch them.


I think this is from one of his 2024 videos:
1728176477945.png

This graph addresses one of the weaknesses of the Chandra paper.
1728176506178.png
 

Rocket Soul

Well-Known Member
A few years ago, Mitch Westmoreland did a study on the impact of temperature on flowering cannabis. That research was part of his work for his PhD and he released a new, much more comprehensive video early this year in which he touches on a variety of topics re. cannabis.

In sum, he recommends letting temps rise to 85° in veg and for the first two weeks, or so, of flower. The reason for this is to maximize the build out of the plant. As of the second week in flower, which is when build out stops, the temps of the tops of the flowers should not exceed 78° in order to preserve cannabanoids. That 78° mark is the maximum and some strains should be even lower.

This is a screenshot from his video.

View attachment 5431284

This is one of two videos that have very similar content. They're superb and I would recommend that every cannabis grower watch them.


I think this is from one of his 2024 videos:
View attachment 5431285

This graph addresses one of the weaknesses of the Chandra paper.
View attachment 5431286
Thx for posting this, ive seen some of mitch work and its very nice.

How well do his results line up with your own? I always try to evaluate the grower behind the study a little bit, always feel i trust a study a little more if i know the grow they studied have been pushed (in general, not only light levels) as hard as we do and their result align with ours.
Checking that yield per dli graph Mitch doesnt seem ahead of the curve for most growers.
We usually push something like 900ppfd/around 40dli which corresponds to around 350g /m. Now that would be a failed crop for us. 35-40% more would be ok/meh results, at 600 per meter we would be real happy. And im fairly sure you outyield mitch aswell, 350 per meter is a very low bar for your standard 35ish w/square foot grow.

I dont know if its down to studies and research having to keep all variable constant; it really help if you can react to stuff happening and change conditions accordingly. Or maybe mitch works with low yield cultivars.

This is not to say theres no validity in this work. But if there wasnt a bunch of papers, numbers and degrees involved: would you make drastic changes to your grow based on the word of a grower that yields about half of what you aspire to yield on the same light levels?
 
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