Welcome to the cannabis questions and answers room. This section is here for you to ask or answer questions regarding cannabis and growing cannabis. To become part of our online cannabis growing community click here to register.

When to switch up light intensity with LEDs

Ask cannabis and growing related questions
User avatar
Keeno
Site Admin
Posts: 25512
Joined: Sat Oct 07, 2017 10:11 pm
Has thanked: 10550 times
Been thanked: 17044 times
Contact:
Status: Offline

Re: When to switch up light intensity with LEDs

Post by Keeno »

Tom I'm sorry, I misread, my advice doesn't work if there are 25% increments. Do you have any room above the light? You could whack it up to 100% and raisie it a bit. You would be shocked the drop off in intensity a few inches can make, this would allow you to turn it up, and lower the light daily.
These users thanked the author Keeno for the post:
Tom1974 (Sun May 29, 2022 10:47 am)

Tom1974
Registered User
Posts: 170
Joined: Tue Apr 19, 2022 8:42 pm
Has thanked: 75 times
Been thanked: 138 times
Status: Offline

Re: When to switch up light intensity with LEDs

Post by Tom1974 »

Keeno wrote:Tom I'm sorry, I misread, my advice doesn't work if there are 25% increments. Do you have any room above the light? You could whack it up to 100% and raisie it a bit. You would be shocked the drop off in intensity a few inches can make, this would allow you to turn it up, and lower the light daily.
No worries man, I turned it up to 100% this morning and raised it to its max

The highest reading on the tallest canopy was 65,000

Surely they won’t bleach at that reading even if the lux meter isn’t 100% accurate it can’t be far off can it?

What’s surprising though is one’s directly next to the highest reading or in front/behind are way off that reading and they don’t look like they are in the shade or anything
These users thanked the author Tom1974 for the post:
Keeno (Sun May 29, 2022 10:57 am)

User avatar
Tom1974
Registered User
Posts: 170
Joined: Tue Apr 19, 2022 8:42 pm
Has thanked: 75 times
Been thanked: 138 times
Status: Offline

Re: When to switch up light intensity with LEDs

Post by Tom1974 »

Lower the light daily, please could you explain buddy?
These users thanked the author Tom1974 for the post:
Keeno (Sun May 29, 2022 10:57 am)

User avatar
Keeno
Site Admin
Posts: 25512
Joined: Sat Oct 07, 2017 10:11 pm
Has thanked: 10550 times
Been thanked: 17044 times
Contact:
Status: Offline

Re: When to switch up light intensity with LEDs

Post by Keeno »

Tom1974 wrote:
Sun May 29, 2022 10:49 am
Lower the light daily, please could you explain buddy?
As in hanging height.

User avatar
Tom1974
Registered User
Posts: 170
Joined: Tue Apr 19, 2022 8:42 pm
Has thanked: 75 times
Been thanked: 138 times
Status: Offline

Re: When to switch up light intensity with LEDs

Post by Tom1974 »

Keeno wrote:
Tom1974 wrote:
Sun May 29, 2022 10:49 am
Lower the light daily, please could you explain buddy?
As in hanging height.
Right, I’ve just whacked it up to it’s max height now and got a reading of 65,000 but the aim is to then start loading the unit bit by bit again?
How close to the tips of the flowers buddy?
Sorry for my ignorance/stupidity

User avatar
seymore_budz
Respected Member
Posts: 2306
Joined: Mon Sep 09, 2019 7:18 pm
Has thanked: 650 times
Been thanked: 1492 times
Contact:
Status: Offline

Re: When to switch up light intensity with LEDs

Post by seymore_budz »

You could guess this but it would be extremely hard without measuring a few parameters of your room. You would need to measure the CO2, Temprature, Humidity & PPFD. Then you could calculate the optimal PPFD with a few calculations. This can be expensive as the equipment to monitor the co2 levels and light output in real-time costs a pretty penny. Also, I'm not sure if that's the full picture.

Stepping into the realm of theory, cannabis thrives all over the world and grows in many climates. Like most plants, different genotypes might like a different climate for example, a plant that has been bred for a European climate may prefer less DLI and a cooler climate yet other cultivars may prefer a Mediterranean climate and enjoy warmer conditions and a higher DLI. As far as I'm aware, not much research has been done within that area?

Considering this, my rule of thumb pre quantum and co2 sensor was try to keep the LED around 40-50cm from the canopy. 25% when they're 10" tall. Increase to 50% for the rest of the duration of growth. Then 75-100% throughout the flowering cycle. Of course this all depends on the output of the LED. My largest LED running my flowering op as an efficency of 2.7mmol/J.

I've light bleached some baby seedlings previously with T5s believe it ir not but never burnt my plants with LED even when tops have been less than 30cm from the LED and its been whacked up. More than often, its not the light that burns things and its the unfavorable environmental conditions like extreme heat, low humidity and crazy amounts of PPFD.
Last edited by seymore_budz on Sun May 29, 2022 11:03 am, edited 1 time in total.
These users thanked the author seymore_budz for the post:
420mFuk (Fri Jun 10, 2022 11:26 am)
Those who can make you believe absurdities can make you commit atrocities.

User avatar
Tom1974
Registered User
Posts: 170
Joined: Tue Apr 19, 2022 8:42 pm
Has thanked: 75 times
Been thanked: 138 times
Status: Offline

Re: When to switch up light intensity with LEDs

Post by Tom1974 »

seymore_budz wrote:You could guess this but it would be extremely hard without measuring a few parameters of your room. You would need to measure the CO2, Temprature, Humidity & PPFD. Then you could calculate the optimal PPFD with a few calculations. This can be expensive as the equipment to monitor the co2 levels and light output in real-time costs a pretty penny. Also, I'm not sure if that's the full picture.

Stepping into the realm of theory, cannabis thrives all over the world and grows in many climates. Like most plants, different genotypes might like a different climate for example, a plant that has been bred for a European climate may prefer less DLI and a cooler climate yet other cultivars may prefer a Mediterranean climate and enjoy warmer conditions and a higher DLI. As far as I'm aware, not much research has been done within that area?

Considering this, my rule of thumb pre quantum and co2 sensor was try to keep the LED around 40-50cm from the canopy. 25% when they're 10" tall. Increase to 50% for the rest of the duration of growth. Then 75-100% throughout the flowering cycle. Of course this all depends on the output of the LED. My largest LED running my flowering op as an efficency of 2.7mmol/J.
Awesome information mate, I’m learning so much on here cheers
These users thanked the author Tom1974 for the post:
seymore_budz (Sun May 29, 2022 11:05 am)

User avatar
seymore_budz
Respected Member
Posts: 2306
Joined: Mon Sep 09, 2019 7:18 pm
Has thanked: 650 times
Been thanked: 1492 times
Contact:
Status: Offline

Re: When to switch up light intensity with LEDs

Post by seymore_budz »

Tom1974 wrote:
Sun May 29, 2022 11:01 am
seymore_budz wrote:You could guess this but it would be extremely hard without measuring a few parameters of your room. You would need to measure the CO2, Temprature, Humidity & PPFD. Then you could calculate the optimal PPFD with a few calculations. This can be expensive as the equipment to monitor the co2 levels and light output in real-time costs a pretty penny. Also, I'm not sure if that's the full picture.

Stepping into the realm of theory, cannabis thrives all over the world and grows in many climates. Like most plants, different genotypes might like a different climate for example, a plant that has been bred for a European climate may prefer less DLI and a cooler climate yet other cultivars may prefer a Mediterranean climate and enjoy warmer conditions and a higher DLI. As far as I'm aware, not much research has been done within that area?

Considering this, my rule of thumb pre quantum and co2 sensor was try to keep the LED around 40-50cm from the canopy. 25% when they're 10" tall. Increase to 50% for the rest of the duration of growth. Then 75-100% throughout the flowering cycle. Of course this all depends on the output of the LED. My largest LED running my flowering op as an efficency of 2.7mmol/J.
Awesome information mate, I’m learning so much on here cheers
No problem. Also remember that this is all based on the plants health. If you're pushing the lights but your PH is out or they're suffering from nutrient deficiencies etc then they might not like all that light. The same way we can turn the pumps up by providing more light, if your plants are not 100% its best to turn those pumps down too. This will slow growth but at the same time give the plants time to focus on recovery. These skills cannot be taught within a few paragraphs here and come with experience.
These users thanked the author seymore_budz for the post:
Tom1974 (Sun May 29, 2022 11:10 am)

Post Reply

Return to “Cannabis And Growing Q&A Room”