LED Grow Light Forum

Thanks SME...it's been a different experience this time around for sure...I'm seeing a LOT more stretch overall in every single plant now...I've checked for light leakage, but haven't seen anything....could it be that the SS400 is just getting a little weaker and the plants are stretching for more light? IDK...I think they said 5 years...I'm at 1 1/2 years now.

Ok, here are the ladies today...day 34 flower, day 72 overall. Temps steady 75-85, RH 40-45...

My blueberry bush



Critical Kush


The Critical Kush seems much more along in development than the others,...look at this cola


Fruity Chronic Juice looking very happy...


Purple Wrecking Crew


Family Shot...you can see the CBD Magma longer stalks I have started to train them to lean over...



Other than the stretch, and perhaps seeming a little bit slower on flowering than I seem to remember from past grows, so far so good!

Any questions, comments or advice always welcomed!
Peace
ICB

I've said it before and I'll say it again, that Fruity Chronic looks amazing. And the Crit... And the Bluebs... They all look great.

I'm not sure on the stretch. I'd think it wouldn't be light output drop. Most light manufacturers base their lifetime hours with LED as "X hours until 70% initial output". In this case, assuming 50k hours until 70%, with a maximum number of hours you could have even run the light being just over 13,000... You might have seen just under 8% light loss. That's IF you ran it 24/7.

End of nerdy math. Beautiful grow!
MC

Hey all, time for the weekly update. MC, thanks for the "nerdy math"...love it. I think I remember reading something like that when I got the SS400...

Ok, so I took these pictures yesterday, on day 38 of flower, day 76 overall. Temps running between 86 daytime to 78 nighttime...RH 37-45...two fans working 24/7, one down low blowing into the closet and the higher one blowing back out.

Feeding every third day, up to full strength, running 1/2 gallon of pure RO through each plant before feeding..seems to be keeping them all happy.

I am now seeing the growth I was hoping for...color me anxious...going back over my other pictures, I can see that I am right on target for development. SME, I am remembering your advice about growing too many strains at once...this time around, I can envision harvesting my CBD Magma and Critical Kush several weeks before the blueberry and fruity chronic juice will be ready...

You can see that the light is about 8 inches above the canopy...closer than I would like, but hey....they seem happy


Here is the blueberry..just getting started, the hairs are still kind of greenish...



Fruity Chronic Juice



Critical Kush



CBD Magma



I missed pics of Purple wrecking crew...next time!

As always, feedback, questions or comments always welcomed!
ICB

MissingCow wrote:I'm not sure on the stretch. I'd think it wouldn't be light output drop. Most light manufacturers base their lifetime hours with LED as "X hours until 70% initial output". In this case, assuming 50k hours until 70%, with a maximum number of hours you could have even run the light being just over 13,000... You might have seen just under 8% light loss. That's IF you ran it 24/7.

End of nerdy math. Beautiful grow!
MC

Technically true (mostly) but there's more to that story and different math may apply. The 50k hours of life often quoted for LED diodes could also be MTBF (mean time between failure) which, like L70, is an estimation and varies from manufacturer to manufacturer. Additionally, there's a difference between LED and System Reliability. Furthermore, the Lumen Maintenance Target varies for different applications. An LED street light might no longer supply a useful amount of light at L60 and a retail LED application might use a L80 target. LED grow lights might even need to have a higher target since plant growth is dependant on light.

According to this article: Do LEDs Lose Light Intensity with Time?

"A good LED grow light should maintain above 70 percent lumen maintenance for over 50,000 hours" but I'm not sure that I agree with Nate on that one. 70% (L70) would be nearly a 1/3 drop in output so a SS440w that starts out with 330-ish watts of power that loses 30% of it's intensity over 50k hours might end up closer to a 230w output light at the end which IS significant when talking about grow lights. While L70 is often used by manufacturers, I don't think I'd consider a 30% drop in intensity (lumens) to be acceptable.

We replace HID bulbs before that much loss why would it be OK for LED? For example, Solis Tek claims in their specs that the 1000w HPS lamps still puts out 92% of it's umols at 20K hours (2.3 years @24hours/day) and nobody that I know runs a HPS bulb that long for growing. If you go by the 8K hour (about 11 months) statistic the bulb would still be producing 97% of it's initial PAR rating. Others claim that HPS bulbs lose 10% in 2-6K hours (2-8 months @24/7) and should be replaced then.

That said, there is a difference between PAR and Lumens but no matter how you measure it I think the loss, over time, would be similar. So...*if* we replace HID bulbs before 90% loss, why should LED grow lights be rated at L70...other than marketing reasons that is?

The other caveat is that not everyone grows cannabis; I'd be willing to bet that that VAST majority of indoor grows do but it IS possible that they use L70 because that could be acceptable for growing lettuce, algae or other non-light-intensive crops....also for marketing reasons.

Would you want *your* grow light to run at 70% of what it should put out or would you want to replace it sooner?

(I should write about this on my blog too)



Now all that said, I don't think ICB's stretch is due to lumen loss over time...yet. I believe it's environmental or genetic.

Hey guys...in going back over this grow journal, and my own journal I keep on poster-sized paper in my grow room, I noted that I did extensive defoliation and pruning this time around, which I did NOT do in the last grows. I compared the heights of CBD Magma and Critical Kush from last grow to this one...at 38 days, when I flipped to 12/12, all plants were 13 inches in height. At 30 days of flowering, the plants this time around have an extra 11 inches in height! Last grow, both CBD Magma and Critical Kush were at 28 inches in height at day 30, and finished at day 62 at 32 inches in height. This time around, the Critical Kush is already 42 inches in height (an almost 30" stretch in 30 days!), and the CBD Magma is 39 inches...

So I am now thinking that a lot of this extra stretch is probably due to stress brought on by so much pruning...SME, I know you are not a fan of defoliating...and this time around, I think my garden is showing signs of that stress you have warned about...

Next grow, just 4 plants, 2 strains....

ItsCurtisBaby wrote:Hey guys...in going back over this grow journal, and my own journal I keep on poster-sized paper in my grow room, I noted that I did extensive defoliation and pruning this time around, which I did NOT do in the last grows. I compared the heights of CBD Magma and Critical Kush from last grow to this one...at 38 days, when I flipped to 12/12, all plants were 13 inches in height. At 30 days of flowering, the plants this time around have an extra 11 inches in height! Last grow, both CBD Magma and Critical Kush were at 28 inches in height at day 30, and finished at day 62 at 32 inches in height. This time around, the Critical Kush is already 42 inches in height (an almost 30" stretch in 30 days!), and the CBD Magma is 39 inches...

So I am now thinking that a lot of this extra stretch is probably due to stress brought on by so much pruning...SME, I know you are not a fan of defoliating...and this time around, I think my garden is showing signs of that stress you have warned about...

Next grow, just 4 plants, 2 strains....

Growing 2 strains, 4 plants... I decided the same thing, thinking that 3 would be too many. I can see where you're getting a headache with all the strains you have! Variety is a good thing though, but it seems like a bit of a logistical nightmare.

I'm interested to hear what SME says on the defoliation stressing the plant to the point of stretching. I always thought defoliation slowed stretch, or stopped it if done extremely. If you have experienced stretch due to defoliation... my world just got turned upside-down!

By the way, I watched an incredible documentary last night and I thought you'd appreciate it. It's on Netflix, called "What do plants talk about?" - it's a PBS doc, and absolutely fascinating! Check it out, maybe with some pineapple chunk to keep you company.

MC

Ahhh extensive defoliation....

Perhaps the plant was stretching to get closer to the light to make up for the lack of leaves?

As mentioned, I've never been a big fan of defoliation; the plants need the leaves for photosynthesis. 13" before flip is pushing it for LED, imho, but not by a lot. 39-42" in flower is certainly too much even for 5w diodes. I'd be aiming for finishing in the 24-36" range and the closer to 24" the better because of the LED penetration issues. You might tie them down LST style this time to keep them shorter...

Hey all, a little late with my weekly update here... Day 50, day 88 overall...

SME, yes, I do think this stretch was due to excessive defoliation as I think about it more and more...it is the only thing that was done differently this time. You can see the lack of penetration to the bottom 1/3 of the plants...oh well, good thing I can start over next month! After a tasty harvest, that is!

Here is my absolute favorite, my blueberry bush..just look at this beauty! She has caught up to the pack tremendously this past week, and is just stunning to look at! Where is smell-a-vision when you need it!




Here is the CBD Magma...she has continued to stretch, even as she has been LST'd over...standing straight up, the tallest cola is 50"...just stupid...but as advertised, this really opened the plant's lower flowers up to an increased amount of light, so it looks like I am going to get a bonanza of mid-sized nuggets. And since I like to grind this high CBD content plant up and add it to pretty much everything I vaporize, that is just fine with me!!




This Critical Kush is absolutely nearing harvest already! Just like last grow, she is showing signs of nute burn...so I fed it half strength today, and anticipate starting her flush next week..




Here is the Purple Wrecking Crew..the main cola is coming along nicely, but the rest of it is lackluster...in an interesting observation, my friend who donated this clone has already harvested his ladies from an outdoor grow...and each one of them ended up as just a single, purple bud sticking out of the ground, from 10-16 inches in height. He was astounded when he saw this plant, and said he had never seen it grown inside before.



This fruity chronic juice is definitely the slowest to develop so far, but she looks the healthiest as well! I can see her having the closet along with the Purple Wrecking Crew for a couple of weeks after the rest have been harvested.


Well, that's it this week. Questions, comments or suggestions always welcomed!
ICB

Just looking at that Critical Kush... my mouth is watering. Outstanding looking buds!

I'm surprised, the CBD looks very very stretchy for what I'm assuming is mostly Indica. I do really like your idea of vaporizing a little of that with every chamber fill. That's a way good way to do it.

And those are massive colas on the blueberries!

All your pistils are pretty light too, which means they should bulk up extra nice in these last few weeks.

Outstanding work as always.
MC

Hey all, time for the weekly update. It's only been 4 days, but I wanted to get back onto my schedule.

Today is day 58 in flower, day 92 overall since sprout.

Still my favorite, my blueberry bush...very healthy all over...pistils are still mostly white, trichomes clear...looking forward to the next 2-3 weeks !




The Critical Kush is very close...nice reddish hairs, trichomes are showing some ambers...(these pics look brighter because of the flash...working on that for next week). Last grow, I harvested this plant on day 58..I'm thinking one more week this time.



The CBD Magma has got some amazing colors coming in as well...oranges and reds...since the stretching and lst'ng, I don't really have "main colas" as much as a plethora of mid size chunks!


The Purple Wrecking Crew is probably 2 weeks away. I'm not all that impressed with this plant...not too robust, not too bulky, eh, it was a gift.


And finally the Fruity Chronic Juice...looking lovely...I'm anticipating harvesting the CBD and the Kush next week, The PWC the week after, and letting the Fruity Chronic and the Blueberry have the closet and the light to themselves...let them finish up really long!



So, lessons learned this time...finally got burned by growing so many different strains at once. SME warned me, and I got lucky a few times...but this time I have made a LOT of extra work for myself...I am looking at 2-3 extra weeks for the slowest plants to finish up...so my closet will be unavailable for the next crop at least that long. Also makes the drying process more of a ....process....

As always, questions, comments or suggestions are welcomed!
ICB