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Cannabis Lighting Is My Thing

jonnywatt

Member
Hi,

I used to post here but haven't in quite some time. I have seen lives saved, including family members, by cannabis and its derivatives. For the past 12 years, I have dedicated what little brainpower I have left to research and development of cannabis (and now hemp) lighting. I am really interested in spectrum delivery and its effect on terpene expression. In the interest of disclosure, I have a lighting company, but my goal is not to promote products, but rather, ideas that benefit everyone when it comes to this wonderful substance and the tons of possible positive uses. I look forward to some lively discussions about lighting and cannabis.

Jonnywatt
 

irie lion

Nug of the Month: May 2019 - Member of the Month: June 2019
Hey Jonny! Welcome back to 420mag :high-five:
Glad to have you and your knowledge on lighting here!
I am really interested in spectrum delivery and its effect on terpene expression.
Yes sir! me too :yahoo:
See you around. Happy growing
 

The Bard

Well-Known Member
Hi @jonnywatt! Welcome (or welcome back) to 420! I'm be interested in following the discussion that emerges on your thread here.

I have a question to kick things off, for you, or anyone else who would like to chime in.

I am using 2x 238W LED boards in my 2x4' tent. The "base" colour temperature is 4000K, and actual draw is 200W per panel according to my kill-a-watt meter. So 400W actual @ 4000K.

In addition, each board has a "deep red booster" on a separate driver, so that I can turn it on during flower to lower to overall colour temperature. Unfortunately, I don't know the exact temperature/wavelength of the red booster. If I recall correctly, the red strip draws about 75W actual.

What are your thoughts regarding running the deep red booster? I am currently running 12/12 for both the 4000K as well as the red. My thinking was the 4000K was good for veg, and then 4000K + red would be good for flowering.

But I have also seen folks mention that they run the red for the first and last hour only of each 12 hour lighting period, not the full 12 hours.

Any thoughts?
 

jonnywatt

Member
Hi @jonnywatt! Welcome (or welcome back) to 420! I'm be interested in following the discussion that emerges on your thread here.

I have a question to kick things off, for you, or anyone else who would like to chime in.

I am using 2x 238W LED boards in my 2x4' tent. The "base" colour temperature is 4000K, and actual draw is 200W per panel according to my kill-a-watt meter. So 400W actual @ 4000K.

In addition, each board has a "deep red booster" on a separate driver, so that I can turn it on during flower to lower to overall colour temperature. Unfortunately, I don't know the exact temperature/wavelength of the red booster. If I recall correctly, the red strip draws about 75W actual.

What are your thoughts regarding running the deep red booster? I am currently running 12/12 for both the 4000K as well as the red. My thinking was the 4000K was good for veg, and then 4000K + red would be good for flowering.

But I have also seen folks mention that they run the red for the first and last hour only of each 12 hour lighting period, not the full 12 hours.

Any thoughts?
Absolutely!

Short version: Run the red full time. I do this for veg AND flower. Make sure you provide enough nutes to satisfy the plant's needs.

Our trials show increased terpene expression when delivering more of a "full" spectrum, from seed to flower. I always remind myself that lighting only sets the potential for our crops. It is the other 1000 things you do that provide for phytochemical content development and yield. Dr David M Gates published a well-respected paper on plant photoreceptor response in which his results show that it takes 1-2 blue photons to process a single CO2 molecule while it takes 8-10 red photons to do the same job.

One thing - In our experience, it is very common to underfeed plants under a more full spectrum light source. One way this is evident is by appearance of "cotton top," especially under LED grow lights. Plants will not use nutrients they don't need, so do not worry about damage, except in DWC or other mediums where roots are constantly in nutrient solution - then root burn is a concern. The trick is to provide enough nutrients while not wasting any ($$$).

1845541


Good luck!
 

The Bard

Well-Known Member
Absolutely!

Short version: Run the red full time. I do this for veg AND flower. Make sure you provide enough nutes to satisfy the plant's needs.

Our trials show increased terpene expression when delivering more of a "full" spectrum, from seed to flower. I always remind myself that lighting only sets the potential for our crops. It is the other 1000 things you do that provide for phytochemical content development and yield. Dr David M Gates published a well-respected paper on plant photoreceptor response in which his results show that it takes 1-2 blue photons to process a single CO2 molecule while it takes 8-10 red photons to do the same job.

One thing - In our experience, it is very common to underfeed plants under a more full spectrum light source. One way this is evident is by appearance of "cotton top," especially under LED grow lights. Plants will not use nutrients they don't need, so do not worry about damage, except in DWC or other mediums where roots are constantly in nutrient solution - then root burn is a concern. The trick is to provide enough nutrients while not wasting any ($$$).

1845541


Good luck!
Thanks for the quick reply! Relieved that running the red booster full time (i.e. 12/12 with the 4000K light) is a good approach.

Can you explain/describe a little more about "cotton top"?

I think that I have been hitting a good balance on the nutes… I don't see any signs of deficiency or excess. Can you elaborate on not causing damage by over-feeding? I am growing in coco, so it is hydro. I find that if I push the nutes too hard, I do get tip burn, and so back off a bit just below that level.

Thanks again!
 

irie lion

Nug of the Month: May 2019 - Member of the Month: June 2019
That's some top quality flower my friend - i look forward to your future grow journals so we can check what you've got growing there! :ganjamon::meatballs:
 

Lowrider72

Well-Known Member
Ahhhh....somebody who understands full spectrum. Welcome back Sir.
315W cmh user here. The spectrum including IR is important.
I grow the most flavoursome buds under cmh full spectrum, muxh better than hps.
My opinion is under 85% full spectrum.... Missing out.
 

jonnywatt

Member
Thanks for the quick reply! Relieved that running the red booster full time (i.e. 12/12 with the 4000K light) is a good approach.

Can you explain/describe a little more about "cotton top"?

I think that I have been hitting a good balance on the nutes… I don't see any signs of deficiency or excess. Can you elaborate on not causing damage by over-feeding? I am growing in coco, so it is hydro. I find that if I push the nutes too hard, I do get tip burn, and so back off a bit just below that level.

Thanks again!
Surely. Examples of cotton top can be seen here:

1845655

1845656

1845657

1845658



Sorry for the camera white balance problem in the first pic. All but one of these was turned around (CT eliminated) by increasing nute delivery.

Also, your tip burn may be a function of the root's exposure to the nutes. Coco has the slightest bit of retention. Have you tried flushing and if so, did the tip burn stop? All of this aside, if you are happy with what you are doing and the medicine is good for you, that's all that matters.
 

jonnywatt

Member
Ahhhh....somebody who understands full spectrum. Welcome back Sir.
315W cmh user here. The spectrum including IR is important.
I grow the most flavoursome buds under cmh full spectrum, muxh better than hps.
My opinion is under 85% full spectrum.... Missing out.
While I am a die-hard LED fan (for now), if anyone ever asks what I would recommend instead, it is CMH! The only other lighting technology that comes close (but is seriously deficient in the power department), is a certain Full Spectrum Fluorescent tube, which shall not be named, lest I get kicked off this board.
 

The Bard

Well-Known Member
Surely. Examples of cotton top can be seen here:

1845655

1845656

1845657

1845658



Sorry for the camera white balance problem in the first pic. All but one of these was turned around (CT eliminated) by increasing nute delivery.

Also, your tip burn may be a function of the root's exposure to the nutes. Coco has the slightest bit of retention. Have you tried flushing and if so, did the tip burn stop? All of this aside, if you are happy with what you are doing and the medicine is good for you, that's all that matters.
Interesting! I am pretty happy so far - it is my first grow, so I am sure that could be doing a lot of things better/smarter. But the girls are alive, and within a week or so of finishing. The end is in sight!

I did start to see some foxtailing on one gal - a Green Crack photoperiod. I don't think it is stress related, as the other girls are all fine. Temps and RH are in the zone, and no light-leaks. So I (and a couple of other guys here on 420 who are much more experienced than I am) am thinking that it is just "natural" foxtailing. The last variable I could think of is the red light, but you have alleviated that concern as well. Here's a pic, just for reference...

1845672


1845673


1845674


Thank you again.
 

jonnywatt

Member
Interesting! I am pretty happy so far - it is my first grow, so I am sure that could be doing a lot of things better/smarter. But the girls are alive, and within a week or so of finishing. The end is in sight!

I did start to see some foxtailing on one gal - a Green Crack photoperiod. I don't think it is stress related, as the other girls are all fine. Temps and RH are in the zone, and no light-leaks. So I (and a couple of other guys here on 420 who are much more experienced than I am) am thinking that it is just "natural" foxtailing. The last variable I could think of is the red light, but you have alleviated that concern as well. Here's a pic, just for reference...

1845672


1845673


1845674


Thank you again.
Beautiful! I can smell them from here!
 

The Bard

Well-Known Member
Beautiful! I can smell them from here!
Thank you! As I said, just happy to have made it this far with plants still alive. I have to say, the Green Crack does smell delicious. Very sweet lemon aroma, kind of like a Hall's cough drop (in a good way). Interested to keep watching this thread and learn from all of you lighting gurus!
 

Alafornia

Grow Journal of the Month: Dec 2019
Welcome, @jonnywatt . Yo momma sho picked a helluva name for ya. :D
 
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