Cannabis Daily Light Integral

Cheese smells very different to our local landraces...
My one neighbour is an ex-police detective.
My sense of smell is very weak though I need to ask my wife if they smell.
She actually complained last week for the first time in a while, but it is to be expected, I flipped the girls into flower.
They always put up a stink in flower.

Slinging PAR said:

Yes, they are dialed in pretty well. Indica dominant hybrid and a sativa that I can only run once a year because it fills up my storage limit. I run both seeds and clones, primarily seeds picking out a good plant from 20 or so to take some cuttings to keep going. Since I know what to expect from these two I haven't ventured far off other than dabbling with a couple of other plants for some variety.

My gpw calculations will be a lot different than how most do it. Farmers use yield per area per grow cycle (year) and I tend to do the same. When calculating power, I take into account total power used (kw hours) since I increase power usage during the grow cycle but that could be broken down into an average over the course of a grow. Plus I veg my plants elsewhere that includes some natural sunlight so how is that accounted for?

My flower chambers are one square meter and are yielding 900-1300g/m2 for the hybrid and 1500-1800g/m2 for the sativa. 7-8 week flower versus 14-16 weeks for the sativa. It is a bit of work to keep everything tidy but the results are worth it.

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Are those numbers per cycle??? If so they are some amazing numbers, up to almost 5oz / square foot on 8 week strain! Id really like to see a thread on your grow cause it sounds out of this world.

Rocket Soul said:

Are those numbers per cycle??? If so they are some amazing numbers, up to almost 5oz / square foot on 8 week strain! Id really like to see a thread on your grow cause it sounds out of this world.

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Yeah those were the ranges for the 4 chambers in the last 2 cycles which is when I started the 6/18 light schedule for flower. I originally intended to increase grow area using the same power per day which by itself can really increase your yield if done properly. What I was surprised with is being able to drop the light power to that which the plant can use during a 24hr cycle and seeing how much power we are wasting just blasting it for 12 hours. Getting the waste energy down from running lights too long is probably the biggest factor for increasing efficiency.

It does take a lot of work. Also a good deal of planning. If you aren't willing to put time into either than you probably won't get good results. Being old probably helps too having more experience, funds and patience for sure. Since I just grow for myself I plan on growing what I will need for a period of time then start another cycle when it is time. In between I will grow other things like veggies if it is in winter.

Don't be surprised when others start reporting similar results as they start do their own testing. Try sog/scrog combined with vertical growing. Towards end of flower, my canopy is tied down so the branches are horizontal forming a plane that rises at about a 60 degree angle and the lights adjusted to hit the canopy at 90 degrees. Air comes in from another chamber to the bottom, filtered and sucked out the top into the next chamber. I am sure there are others who have come up with something similar or even better.

Show some pictures of your setup? it's hard to imagine all the things you write down sometimes you feel me? @Slinging PAR

I ask this question again since u didnt answer my reply, does this lighting schedule have a name? Will make it easier to do my own research like you suggested.

And dont assume i have limitations because im honest. If you want to grow the best quality meds you actually need to put in alot of time and effort to get it perfect. Ofcourse you can sacrifice quality by making more work for yourself might even gain some yield. But if you give the care and attention I give my plants. it's not humanly impossible for anyone to run 4 of those chambers, it's impractical for sleep and mental health is what im saying. But if the light schedule really works like you say and it doesnt affect quality, then I would consider running two chambers that would probably managable over a longer period of time for one person imo. Whole other case tho if I was running a facility that supplies dispensaries, then I would hire a crew and run 4 chambers 6 hours on per day.

truly i am interested in the growing technique. I apologise if my questions seem rude, im genuinly curious to learn. Id apprechiate any link or hints as to where I could find research on this light schedule..

edit: I did say impossible in my first reply that was wrong. I was thinking optimal.

Slinging PAR said:

Either or works, and yes I have measured it with IR before. Now I don't bother as the droop is the indicator I use to adjust time on and ppfd hitting the canopy.



That could be a reason if that was a problem but I have this dialed in quite well so I know that the drooping is a sign that the plant is done for the day. Like everything else the plant will tell you want it needs and has enough of.




Heat will increase if it can't be managed by the plant and the environment. Ambient, air flow, RH, VPD, even altitude are variables in play.

Yes we can deliver minimum, optimal and maximum DLI for any plant using today's tech. 1 DLI = 275 ppfd for 1 hour. High energy plants that can handle 65 DLI works out to about 900 ppfd for 24hrs or 1800 ppfd for 12 hours.

Whether that is optimal is a different story.

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Fascinating stuff!
I want to make sure I get this.
So you're saying the "optimal" amount of light (or DLI) for a plant in a day is when the leaves start to sag? That is basically when the plant taps out for the day and any extra photons are basically wasted?
I would love to see pics of your grow.
Thanks.

BuddyColas said:

Fascinating stuff!
I want to make sure I get this.
So you're saying the "optimal" amount of light (or DLI) for a plant in a day is when the leaves start to sag? That is basically when the plant taps out for the day and any extra photons are basically wasted?
I would love to see pics of your grow.
Thanks.

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Yes. Natural reaction for the plant to adverse conditions is droop. So long as everything else is fine it will be caused by too much light.

Slinging PAR said:

Yes. Natural reaction for the plant to adverse conditions is droop. So long as everything else is fine it will be caused by too much light.

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I have learned for instance to recognize when they are thirsty by looking at the lower leaves for drooping.
It shows there hours before the rest of the plant shows signs.

Slinging PAR said:

Yes. Natural reaction for the plant to adverse conditions is droop. So long as everything else is fine it will be caused by too much light.

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Great. I have noticed that the leaves start to sag the last couple of hours in the day in my garden.


*BTW, I too am an old guy with a little time, and resources and patience to devote to growing. We gotta help each other!


So in post #66 you said, “It is about the same, nothing noticeably different, a day or two on either side maybe?” So once you determine the optimal DLI for you plant, then if you take 6 hours or 12 hours to deliver that optimal DLI, it doesn’t really make that much difference in finish time or yield?

Some guy asked for a source earlier and instead of providing him with one you were just plain rude to him. Why are you mad about ppl wanting scientific research on this? Should take it as a compliment really, we're curious on something you suggested and want to know more frankly.. How long have you run 4 flowering chambers on this schedule?

Slinging PAR said:

Yeah those were the ranges for the 4 chambers in the last 2 cycles which is when I started the 6/18 light schedule for flower. I originally intended to increase grow area using the same power per day which by itself can really increase your yield if done properly. What I was surprised with is being able to drop the light power to that which the plant can use during a 24hr cycle and seeing how much power we are wasting just blasting it for 12 hours. Getting the waste energy down from running lights too long is probably the biggest factor for increasing efficiency.

It does take a lot of work. Also a good deal of planning. If you aren't willing to put time into either than you probably won't get good results. Being old probably helps too having more experience, funds and patience for sure. Since I just grow for myself I plan on growing what I will need for a period of time then start another cycle when it is time. In between I will grow other things like veggies if it is in winter.

Don't be surprised when others start reporting similar results as they start do their own testing. Try sog/scrog combined with vertical growing. Towards end of flower, my canopy is tied down so the branches are horizontal forming a plane that rises at about a 60 degree angle and the lights adjusted to hit the canopy at 90 degrees. Air comes in from another chamber to the bottom, filtered and sucked out the top into the next chamber. I am sure there are others who have come up with something similar or even better.

Click to expand...

Ok, vertical-ish.

There are some things in this that makes sense to me and some that dont.
Dont: theres a paper thats been thrown around more than a few times on her that shows a graph on light-levels, showing that over 800 mmols the efficiency of photosynthesis starts dropping quite a lot. Sadly i dont know all the details, just looking at the graph really, and its possible that the whole paper is based on 12/12 and doesnt really factor in optimal DLI, just that too much light per cycle is no bueno.

Does: if i understand plant physiology correctly but please correct me if im wrong: the plant doesnt really do the growing during the day, it grows during the night. During the day it photosynthesize sugars, breathing CO2. These same sugars are then spent or "eaten" by the plant during night time when the energy gained thru burning them so the plant can grow. This process creates CO2, as quoted in many GML episodes. So you also get CO2 without having to use tanks or burners. Car analogy: it spends the day "filling up gas" and the night "making miles", more time "driving" more miles.
Torontoke (i think?) was the one who quoted seriously reduced flowering times with same yields as 12/12 using 8/16 hours. If youre running your strains the same amounts of weeks as before increased yields might be the other side of the same coin.

@torontoke was indeed the guy who started posting about drastically reducing lights on times. He took a lot of grief for it from people who were terrified of anything that challenged their notions about how plants 'are supposed to grow'.

One big difference between his observations and those of @Slinging PAR is that he said his plants finished much faster and slinging PAR said he found otherwise. No one has to be wrong, I'm curious about why the difference might exist.

Slinging PAR said:

900-1300g/m2 for the hybrid and 1500-1800g/m2 for the sativa. 7-8 week flower versus 14-16 weeks for the sativa

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any pics, bro? sounds mighty impressive - especially the 1800g per square meter sativa. That's a lot of weed in a small space!

your Hashplant/Chem4 x Fire OG Day 70 was rather lovely

BuddyColas said:

Great. I have noticed that the leaves start to sag the last couple of hours in the day in my garden.


*BTW, I too am an old guy with a little time, and resources and patience to devote to growing. We gotta help each other!


So in post #66 you said, “It is about the same, nothing noticeably different, a day or two on either side maybe?” So once you determine the optimal DLI for you plant, then if you take 6 hours or 12 hours to deliver that optimal DLI, it doesn’t really make that much difference in finish time or yield?

Click to expand...

You got it. That is how I am going to be running plants from now on. Figure out how much light they can use per day and keep it around that level. Then use that information to maximize the next run with that strain. It has saved me a lot in power which makes it worthwhile.

Rocket Soul said:

Ok, vertical-ish.

There are some things in this that makes sense to me and some that dont.
Dont: theres a paper thats been thrown around more than a few times on her that shows a graph on light-levels, showing that over 800 mmols the efficiency of photosynthesis starts dropping quite a lot. Sadly i dont know all the details, just looking at the graph really, and its possible that the whole paper is based on 12/12 and doesnt really factor in optimal DLI, just that too much light per cycle is no bueno.

Does: if i understand plant physiology correctly but please correct me if im wrong: the plant doesnt really do the growing during the day, it grows during the night. During the day it photosynthesize sugars, breathing CO2. These same sugars are then spent or "eaten" by the plant during night time when the energy gained thru burning them so the plant can grow. This process creates CO2, as quoted in many GML episodes. So you also get CO2 without having to use tanks or burners. Car analogy: it spends the day "filling up gas" and the night "making miles", more time "driving" more miles.
Torontoke (i think?) was the one who quoted seriously reduced flowering times with same yields as 12/12 using 8/16 hours. If youre running your strains the same amounts of weeks as before increased yields might be the other side of the same coin.

Click to expand...

It doesn't say the light cycle used to determine those numbers. Most likely you are correct that it was based on 12/12 light schedule.

800 ppfd for 12 hours is around 36 DLI which sounds about right. Going over that may give you small increases but nothing like the increases seen from 10-20 DLI which is usually when the plant is taking off in veg.

Do read up on dark cycle reactions. Calvin cycle. All that has to do with photosynthesis. Fine tune everything.

For your car analogy also consider that driving at night may get you to your destination faster, with less gas, etc, because there is less traffic on the road and you are able to drive more efficiently.

In my opinion, outside of scientific studies, using supplemental CO2 generation is somewhat unnecessary as you can get more CO2 to the plant with increased airflow. That also helps with the heat. If you want more then go hangout in the grow area and sing to your plants

ttystikk said:

@torontoke was indeed the guy who started posting about drastically reducing lights on times. He took a lot of grief for it from people who were terrified of anything that challenged their notions about how plants 'are supposed to grow'.

One big difference between his observations and those of @Slinging PAR is that he said his plants finished much faster and slinging PAR said he found otherwise. No one has to be wrong, I'm curious about why the difference might exist.

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It is difficult to improve if you aren't willing to try new things. There will always be naysayers afraid to consider anything outside of their knowledge-base and comfort zones. The great thing about the internet is it comes with tools that help to ignore ignorance!

Many different things could explain the difference in finishing times. Main ones I can think of is when the grower chooses to harvest, tastes are different, different strains, etc. I have also been running these strains for a long time (even under other lighting) and am confident to say that I am close to if not reaching the potential for these strains. You can't replace or discount experience.

lukio said:

any pics, bro? sounds mighty impressive - specially the 1800g per square meter sativa. That's a lot of weed in a small space!

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I would post pictures but I do like to travel to the US from time to time, so no, until it is legal federally in the US, I probably won't. Don't mind sharing information but not at the cost of my freedom.

The sativa is a beast and reaches the top of the chamber, I have to curl it around the corners and some branches lap over onto the bottom branches. I use a makeshift chicken wire cage around the filter to keep the leaves for getting sucked against it. The way the lights were positioned at that stage almost all of the light was hitting leaf, not much being reflected back out. As a result it it gives the appearance that it isn't so bright in there as you would think it should be. Then I empty it out and bling, have to turn the lights back down.

Slinging PAR said:

but not at the cost of my freedom.

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that's fair enough, dude.

sorry, i edited my post - what about the Hashplant/Chem4 x Fire OG ? that looked amazing.

its been an interesting read. i gave my plants less light this round and my weights were surprisingly high. i was aiming for around 800 ppfd, granted im not the most techy and things are pretty guesstimated but the girls seemed to produce! it was also @captainmorgan that put me onto this...cheers fella!

Rahz said:

I recently helped someone replace 2 600w HPS with 1120w LED. I let them borrow my par meter and asked them to take readings before and after. The HPS was reading 1022 PPFD 16" below center and 678 PPFD near the side, approximately 16" off center. Readings were also taken 22" below center (752 PPFD) and 22" off center (330 PPFD).

Anyway, this person had one plant that was a late addition and he angled both of his HIDs onto the plant since he didn't need the whole space at the time. Got the biggest buds he's ever gotten. He does run CO2. His light levels at the canopy were likely between 1500 and 2000. Unfortunately I don't have a way to quantify the difference, but he was impressed.

If anyone is curious, the 51% efficient LED that replaced the HID at same reading points were 1408/820 and 1011/605. The bulbs were six months old so they didn't get beaten that badly, but still a major improvement.

Point is, if you hang your lamps too high you're wasting light and loosing yield. I haven't had a chance to play around with HID but one thing I've noticed with LED, especially using 90 degree reflectors is that the center point reading will be somewhat linear while the outer readings will stall for a bit. What I mean by that is for instance you are checking light levels at 12 inches and get maybe 1000 center and 600 side. Move down to 14 inches and your at 850/620 or something similar. Then at 18" it's 700/590. This happens on the side because although the reading is being taken further away which lowers readings it's also further inside the cone which raises readings. This is why you should get your lights as close as they can tolerate within reason. Moving up from 12" to 10 inches in the same example might produce 1200/430 or something similar as the side reading moves outside the cut off point of the reflector cone.

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Run with reflectors or bare COBS even lower ?

Strange how the plants need less light as the flowering progresses.
My plants were giving a hard no these last two hours already and it is still 45 minutes to lights out
Top leaves are lifted up about as high as the plants can manage. I lifted the lights a few inches now. WIll see how it looks tomorrow towards the end of the day.

ANC said:

Cheese smells very different to our local landraces...
My one neighbour is an ex-police detective.
My sense of smell is very weak though I need to ask my wife if they smell.
She actually complained last week for the first time in a while, but it is to be expected, I flipped the girls into flower.
They always put up a stink in flower.

Click to expand...

Think vaping causes loss in sense of smell ?

Naaah, but a lifetime of heavy smoking will.

ANC said:

Strange how the plants need less light as the flowering progresses.
My plants were giving a hard no these last two hours already and it is still 45 minutes to lights out
Top leaves are lifted up about as high as the plants can manage. I lifted the lights a few inches now. WIll see how it looks tomorrow towards the end of the day.

Click to expand...

I'm interested in your observations. If your observations are correct, you can tailor your plant's "photon diet" or DLI to what ever the plants top leaves are tell you at whatever stage the plant is in. So optimal photosynthesis all the way through. Sweet.