The Mountain: Grow Support From The Over 50 Club

[ppm Charlie]

I heard someone recently state the new LED lights (I'll assume a Samsung 301 diode) should be somewhere between 25-40 watts/sf. At 250 watts/sf you must spend a whopping amount on energy. With this much energy into a 4X8 you do have a heat problem that's why you run your exhaust, that and humidity right. You replace this air with fresh cold drier air that you pay to heat, humidify, and exhaust.
You should only need about 1500 watts of diodes for 32sf. That is a lot less heat so you can turn down your constant exhaust fan (keep your circulation fans running). With your extraction fan turned down you are not constantly sucking in so much dry air. Maybe you may not need a humidifier but, a dehumidifier instead.
I don't want to have a debate about VPD, PAR, Temp. There are other more energy efficient ways to accomplish your same goals. Lots of ways to crack eggs.

Possibly. The LED vendor says each 2,000-watt LED light is good for an approximately 2 X 4 grow space, hence 4 light panels spread over the 8-foot length of the tent. A dehumidifier uses a lot more energy than a small ultrasonic humidifier, I think (I use distilled water in it). The need for a humidifier has more to do with the dry Fall weather conditions recently which has put the house humidity and intake tent air at the 45% RH level. With the LEDs lighted, the flowering tent humidity drops to 32-35% RH. For flowering 40% to 45% is good.

I just put my veg tent 420 in the flowering tent so I am trying to reduce the RH slowly over 5-10 days to the 40% RH level (in the veg tent the 420 had humidity of 50%-60% RH). It is at about 43%-45% RH currently. At the very end of flowering I may not need the humidifier since 30%-35% RH can be run in the last week or so before harvest (I have read).

This is my first grow in a long time so the tents and equipment are all new and I am experimenting a little to find the "right" groove. Each light pulls about 200 actual watts and the extraction fan is dialed back to about 60% of it's full capacity. I am probably turning over an air volume equal to the tent volume each minute. Most growers recommend at least one volume each three minutes (but that is the minimum air turnover rate). I will check out these conditions and see if I get a winner, if not, I will change the setup.

 

[Delps8]

I heard someone recently state the new LED lights (I'll assume a Samsung 301 diode) should be somewhere between 25-40 watts/sf. At 250 watts/sf you must spend a whopping amount on energy. With this much energy into a 4X8 you do have a heat problem that's why you run your exhaust, that and humidity right. You replace this air with fresh cold drier air that you pay to heat, humidify, and exhaust.
You should only need about 1500 watts of diodes for 32sf. That is a lot less heat so you can turn down your constant exhaust fan (keep your circulation fans running). With your extraction fan turned down you are not constantly sucking in so much dry air. Maybe you may not need a humidifier but, a dehumidifier instead.
I don't want to have a debate about VPD, PAR, Temp. There are other more energy efficient ways to accomplish your same goals. Lots of ways to crack eggs.

I suspect that @ppmCharlie is describing his LED’s as "2,000-watt LED panel lights” because manufacturers describe their lights as being replacements for HID’s of that wattage for they phrase is as “X watts equivalent". I’m no expert on commercially available lights but looking across Mars, Chilled, and few others, the largest LEDs have a max draw for <= 1000 watts. The main reason for that is, I suspect, that an 800 ro 1k watt LED generates enough light to saturate a 5’ x 5’ area (the second attachment is from ppfdcharts.com).

Also, it would be very difficult to fit 4 large LEDs into a 32 sq ft space. The Growcraft is 3.5’ square and the Mars is 3.8 ft square.

“With this much energy into a 4X8 you do have a heat problem that's why you run your exhaust, that and humidity right.”
That would well be the case with incandescents. Even at full output, the temperature of a modern LED fixture from will be in the 120±°F range. The driver will get warm but the panels run very cool. That becomes an issue in cooler climates - with no burning filament, the ambient temperature when using LED’s should be raised by 10°F to compensate.

At the moment, my Growcraft X3 is providing the PPFD shown in the attachment. Hang height is about 6” (is was 6” yesterday but the plants have grown into the light). The temperature of the light bars ranges from 82° to 88° while the temperature of the driver varies from 98° to 104°. The light is drawing 158 watts from a 120 volt circuit. My grow is in an unheated garage in SoCal and I’m considering moving the driver into the tent since the overnight lows are dipping into the 50’s. It’s not a lot of heat but it’s better off being in the tent than keeping a car warm.

PPFD is measured with Apogee MQ-500 PAR meter.

 

[Delps8]

Just saw that @ppmCharlie replied.

Oh well…

 

[Vegan4life]

Lots of the cheaper LED light fixture manufacturers state that there fixtures wattage is what potential the led’s could draw or what they are rated for. When the fixure itself is only drawing what wattage the driver is pulling. Kind of a bait and switch...

 

[ppm Charlie]

I suspect that @ppmCharlie is describing his LED’s as "2,000-watt LED panel lights” because manufacturers describe their lights as being replacements for HID’s of that wattage for they phrase is as “X watts equivalent". I’m no expert on commercially available lights but looking across Mars, Chilled, and few others, the largest LEDs have a max draw for <= 1000 watts. The main reason for that is, I suspect, that an 800 ro 1k watt LED generates enough light to saturate a 5’ x 5’ area (the second attachment is from ppfdcharts.com).

Also, it would be very difficult to fit 4 large LEDs into a 32 sq ft space. The Growcraft is 3.5’ square and the Mars is 3.8 ft square.

“With this much energy into a 4X8 you do have a heat problem that's why you run your exhaust, that and humidity right.”
That would well be the case with incandescents. Even at full output, the temperature of a modern LED fixture from will be in the 120±°F range. The driver will get warm but the panels run very cool. That becomes an issue in cooler climates - with no burning filament, the ambient temperature when using LED’s should be raised by 10°F to compensate.

At the moment, my Growcraft X3 is providing the PPFD shown in the attachment. Hang height is about 6” (is was 6” yesterday but the plants have grown into the light). The temperature of the light bars ranges from 82° to 88° while the temperature of the driver varies from 98° to 104°. The light is drawing 158 watts from a 120 volt circuit. My grow is in an unheated garage in SoCal and I’m considering moving the driver into the tent since the overnight lows are dipping into the 50’s. It’s not a lot of heat but it’s better off being in the tent than keeping a car warm.

PPFD is measured with Apogee MQ-500 PAR meter.

Yes, the vendor describes the LED lights as their 2,000 "series", not 2,000-watt, my mistake. The vendor says one light would replace a 400-watt HID or HPS. Thank you for pointing that out - my fingers sometimes work faster than my brain.

With all the lights running and without the extraction fan running flowering tent temps approach 95-99 deg F. The heat is mainly generated by the drivers on top of the lights. I would relocate the drivers from the top of the light fixtures, however, the LED vendor does not recommend it and said it would void the warranty if I did. I say they are "panel" LEDs because the LEDs are grouped together on one rectangular aluminum panel measuring 24" X 10.8". This is a good size for my rectangular tent configuration.

You said: "My grow is in an unheated garage in SoCal and I’m considering moving the driver into the tent since the overnight lows are dipping into the 50’s. It’s not a lot of heat but it’s better off being in the tent than keeping a car warm."

I say: You could always leave the drivers outside the tent and place them at the air inlet area and that would provide more heat at night for your 420 (with or without intake air fan). I assume you run your lights at night.

 

[Delps8]

Yes, the vendor describes the LED lights as their 2,000 "series", not 2,000-watt, my mistake. The vendor says one light would replace a 400-watt HID or HPS. Thank you for pointing that out - my fingers sometimes work faster than my brain.

As long as that's a temporary condition, you're doing fine. I recently turned fifty fifteen and, for the past couple of years, I've noticed that I'm capitalizing the second letter of a word when I type. Heh, if that was the worst thing I'd be a lucky SOB, eh?

With all the lights running and without the extraction fan running flowering tent temps approach 95-99 deg F. The heat is mainly generated by the drivers on top of the lights. I would relocate the drivers from the top of the light fixtures, however, the LED vendor does not recommend it and said it would void the warranty if I did. I say they are "panel" LEDs because the LEDs are grouped together on one rectangular aluminum panel measuring 24" X 10.8". This is a good size for my rectangular tent configuration.

95-99 - open the vents and run the fan. That's a battle but you're getting good light and a good harvest so you're on the right track.

You said: "My grow is in an unheated garage in SoCal and I’m considering moving the driver into the tent since the overnight lows are dipping into the 50’s. It’s not a lot of heat but it’s better off being in the tent than keeping a car warm."

I say: You could always leave the drivers outside the tent and place them at the air inlet area and that would provide more heat at night for your 420 (with or without intake air fan). I assume you run your lights at night.

The X3 is at 6" hang height so the wattage that it's consuming is really low - 159 watts. It just doesn't give off an appreciable amount of warmth. There's no particular "inlet" - it's a 2' x 4' Gorilla tent in the 20' x 25' garage. Fortunately, the wall behind the tent is south facing and my POSSLQ drives a car almost daily so that helps keep the temp up.

 

[MAK1]

Possibly. The LED vendor says each 2,000-watt LED light is good for an approximately 2 X 4 grow space, hence 4 light panels spread over the 8-foot length of the tent. A dehumidifier uses a lot more energy than a small ultrasonic humidifier, I think (I use distilled water in it). The need for a humidifier has more to do with the dry Fall weather conditions recently which has put the house humidity and intake tent air at the 45% RH level. With the LEDs lighted, the flowering tent humidity drops to 32-35% RH. For flowering 40% to 45% is good.

I just put my veg tent 420 in the flowering tent so I am trying to reduce the RH slowly over 5-10 days to the 40% RH level (in the veg tent the 420 had humidity of 50%-60% RH). It is at about 43%-45% RH currently. At the very end of flowering I may not need the humidifier since 30%-35% RH can be run in the last week or so before harvest (I have read).

This is my first grow in a long time so the tents and equipment are all new and I am experimenting a little to find the "right" groove. Each light pulls about 200 actual watts and the extraction fan is dialed back to about 60% of it's full capacity. I am probably turning over an air volume equal to the tent volume each minute. Most growers recommend at least one volume each three minutes (but that is the minimum air turnover rate). I will check out these conditions and see if I get a winner, if not, I will change the setup.

Thanks for the input here. I'll get into trouble here ... I do not agree with the advice on air exchange estimates. What is the reason for this fresh air intake? Mold? I like to have lots of circulation air but I'm reluctant to heat any extra air probably because it is a lot colder where I live and propane is already double last years high. $$$

 

[MAK1]

Yes, the vendor describes the LED lights as their 2,000 "series", not 2,000-watt, my mistake. The vendor says one light would replace a 400-watt HID or HPS. Thank you for pointing that out - my fingers sometimes work faster than my brain.

With all the lights running and without the extraction fan running flowering tent temps approach 95-99 deg F. The heat is mainly generated by the drivers on top of the lights. I would relocate the drivers from the top of the light fixtures, however, the LED vendor does not recommend it and said it would void the warranty if I did. I say they are "panel" LEDs because the LEDs are grouped together on one rectangular aluminum panel measuring 24" X 10.8". This is a good size for my rectangular tent configuration.

You said: "My grow is in an unheated garage in SoCal and I’m considering moving the driver into the tent since the overnight lows are dipping into the 50’s. It’s not a lot of heat but it’s better off being in the tent than keeping a car warm."

I say: You could always leave the drivers outside the tent and place them at the air inlet area and that would provide more heat at night for your 420 (with or without intake air fan). I assume you run your lights at night.

I don't know where in here there was reference to 10 degrees higher room temps when using these new LED's. I can't find it. Anyhow, there are times when the leaves are pointing up towards the light and now I suspect this might coincide with when the room temps are higher. Does this sound right? The plants look awesome and when the leaves point upwards they look even better, this is a good thing right?
I have another lamp coming(Amazon says Tuesday) that will increase the room temps and I have concerns.

 

[Old Guy Teaches]

This may sound silly... But your in So Cal.?? why Not just grow outside in 20/25 Gal Felt Pots and some Fox Farm soil. Some nutes from General Hydro, [Grow and BlooM] from clones and your done....Period a good meter for PH set to 6.1. Plant in March and harvest in Oct. Use a tablespoon of magnesium for a Month Like epson salts. and some good clones available just about everywhere. I reccomend "Sour Diesel" and your done. seems a Lot of folks here go right past it.
It's a weed man......... Not rocket science. I grow 15/20 footers every year that is the best there is. About as Dumb as it gets My Friend.

 

[MAK1]

This may sound silly... But your in So Cal.?? why Not just grow outside in 20/25 Gal Felt Pots and some Fox Farm soil. Some nutes from General Hydro, [Grow and BlooM] from clones and your done....Period a good meter for PH set to 6.1. Plant in March and harvest in Oct. Use a tablespoon of magnesium for a Month Like epson salts. and some good clones available just about everywhere. I reccomend "Sour Diesel" and your done. seems a Lot of folks here go right past it.
It's a weed man......... Not rocket science. I grow 15/20 footers every year that is the best there is. About as Dumb as it gets My Friend.

 

[ppm Charlie]

Thanks for the input here. I'll get into trouble here ... I do not agree with the advice on air exchange estimates. What is the reason for this fresh air intake? Mold? I like to have lots of circulation air but I'm reluctant to heat any extra air probably because it is a lot colder where I live and propane is already double last years high. $$$

I believe that thriving plants need CO2 as one important component for proper photosynthesis. If air circulation is overly restricted, CO2 in the grow space drops down and the plants are not getting all they need. Also, humidity, mold and fungi are an issue in poorly ventilated grows.

 

[ppm Charlie]

I don't know where in here there was reference to 10 degrees higher room temps when using these new LED's. I can't find it. Anyhow, there are times when the leaves are pointing up towards the light and now I suspect this might coincide with when the room temps are higher. Does this sound right? The plants look awesome and when the leaves point upwards they look even better, this is a good thing right?
I have another lamp coming(Amazon says Tuesday) that will increase the room temps and I have concerns.

You are correct, there is no reference(s) in my posts to those LED light studies that indicate 10 deg F hotter for LED plant lighting as compared to HID and HPS. I have tried to post those web links in previous posts here at the 420 Magazine website and run into a problem. Apparently, LED light sponsors on this website pay money and gift equipment, services and supplies to sponsor ads and ad forums for the readers and growers here. 420 Magazine relies are their exceptional and high quality paying sponsors to supply 420 Magazine revenue to operate.

When I have tried to post those LED light studies, I have been edited by this website's administrators and those web links removed from my posts. Reason being...spammers seeking free advertising and, 420 Magazine and their paying sponsors not wanting web links appearing here at the 420 website that are not paying sponsors (why give a non-sponsor vendor free advertising?). The web links I referenced to the LED light studies are not sponsors of this website. Plus, 420 Magazine does not want spammers inflicting their website seeking free advertising and making the website messy and low quality. More information on 420 Magazine policies here: Questions & Answers - LEDs

Makes complete sense, it is fair and I accept that 420 Magazine could not operate without high quality paying sponsors (a BIG SHOUT OUT to all 420's paying sponsors - Thank You Kindly!). Therefore, no web links can be posted that indicate 10 deg F hotter for LEDs as compared to HID or HPS.

If you search the web for "leaf surface temperature studies of cannabis", I am sure you will find those references.

 

[ppm Charlie]

This may sound silly... But your in So Cal.?? why Not just grow outside in 20/25 Gal Felt Pots and some Fox Farm soil. Some nutes from General Hydro, [Grow and BlooM] from clones and your done....Period a good meter for PH set to 6.1. Plant in March and harvest in Oct. Use a tablespoon of magnesium for a Month Like epson salts. and some good clones available just about everywhere. I reccomend "Sour Diesel" and your done. seems a Lot of folks here go right past it.
It's a weed man......... Not rocket science. I grow 15/20 footers every year that is the best there is. About as Dumb as it gets My Friend.

DANG!

 

[ppm Charlie]

This may sound silly... But your in So Cal.?? why Not just grow outside in 20/25 Gal Felt Pots and some Fox Farm soil. Some nutes from General Hydro, [Grow and BlooM] from clones and your done....Period a good meter for PH set to 6.1. Plant in March and harvest in Oct. Use a tablespoon of magnesium for a Month Like epson salts. and some good clones available just about everywhere. I reccomend "Sour Diesel" and your done. seems a Lot of folks here go right past it.
It's a weed man......... Not rocket science. I grow 15/20 footers every year that is the best there is. About as Dumb as it gets My Friend.

I do not live in an area that has legalized recreational cannabis...wish I did. Therefore, no outside grows. I will take your Sour Diesel advice though...looks very promising.

 

[MAK1]

I believe that thriving plants need CO2 as one important component for proper photosynthesis. If air circulation is overly restricted, CO2 in the grow space drops down and the plants are not getting all they need. Also, humidity, mold and fungi are an issue in poorly ventilated grows.

So many different growing environments. The experts have all their conditions set a certain way and, for their set-up it was determined by etherial clouds that every three minutes was a good amount of air to reduce mold risks. This has nothing to do with CO2 concentration, unless you play that CO2 game. Plants respire, tents have holes. It is impossible for us home growers restrict CO2 to the point of harming a plant. Adding extra CO2 isn't going to help enough to matter without a better sealed greenhouse system.
Fresh air is unavoidable. Is it even possible to maintain a CO2 level below 150ppm? How much more will we get if it is very high? Not a fan of this CO2 story. I'm not buying it. Keep your air moving. No one ever has mold in a windy area.

 

[MAK1]

I do not live in an area that has legalized recreational cannabis...wish I did. Therefore, no outside grows. I will take your Sour Diesel advice though...looks very promising.

Don't forget the magic of Fox Farm soil, maybe a tasty choice like some Happy Frog, assuming the Old Guy Teaches would approve.

 

[MAK1]

This may sound silly... But your in So Cal.?? why Not just grow outside in 20/25 Gal Felt Pots and some Fox Farm soil. Some nutes from General Hydro, [Grow and BlooM] from clones and your done....Period a good meter for PH set to 6.1. Plant in March and harvest in Oct. Use a tablespoon of magnesium for a Month Like epson salts. and some good clones available just about everywhere. I reccomend "Sour Diesel" and your done. seems a Lot of folks here go right past it.
It's a weed man......... Not rocket science. I grow 15/20 footers every year that is the best there is. About as Dumb as it gets My Friend.

Old Guy: Do you change/replace your soil from time to time or is this the tilth you developed over years?

 

[MAK1]

You are correct, there is no reference(s) in my posts to those LED light studies that indicate 10 deg F hotter for LED plant lighting as compared to HID and HPS. I have tried to post those web links in previous posts here at the 420 Magazine website and run into a problem. Apparently, LED light sponsors on this website pay money and gift equipment, services and supplies to sponsor ads and ad forums for the readers and growers here. 420 Magazine relies are their exceptional and high quality paying sponsors to supply 420 Magazine revenue to operate.

When I have tried to post those LED light studies, I have been edited by this website's administrators and those web links removed from my posts. Reason being...spammers seeking free advertising and, 420 Magazine and their paying sponsors not wanting web links appearing here at the 420 website that are not paying sponsors (why give a non-sponsor vendor free advertising?). The web links I referenced to the LED light studies are not sponsors of this website. Plus, 420 Magazine does not want spammers inflicting their website seeking free advertising and making the website messy and low quality. More information on 420 Magazine policies here: Questions & Answers - LEDs

Makes complete sense, it is fair and I accept that 420 Magazine could not operate without high quality paying sponsors (a BIG SHOUT OUT to all 420's paying sponsors - Thank You Kindly!). Therefore, no web links can be posted that indicate 10 deg F hotter for LEDs as compared to HID or HPS.

If you search the web for "leaf surface temperature studies of cannabis", I am sure you will find those references.

Dang Charlie, THANKS! I am on it.
I am very curious why sometimes the leaves are pointing to the sky? Is this simply the extra heat?

 

[ppm Charlie]

So many different growing environments. The experts have all their conditions set a certain way and, for their set-up it was determined by etherial clouds that every three minutes was a good amount of air to reduce mold risks. This has nothing to do with CO2 concentration, unless you play that CO2 game. Plants respire, tents have holes. It is impossible for us home growers restrict CO2 to the point of harming a plant. Adding extra CO2 isn't going to help enough to matter without a better sealed greenhouse system.
Fresh air is unavoidable. Is it even possible to maintain a CO2 level below 150ppm? How much more will we get if it is very high? Not a fan of this CO2 story. I'm not buying it. Keep your air moving. No one ever has mold in a windy area.

I would respectfully disagree with your argument regarding full replenishment of CO2 in a grow tent air volume through diffusion rather than air transfer (intake port and exhaust fan). You are correct in asserting that CO2 easily diffuses into the tent space (i.e. through zippers, through the tent material itself and through vent openings not closed tightly). I think what it comes down to is the rate of CO2 diffusion. Is cannabis in a grow tent actually using more CO2 for photosynthesis/transpiration during intensive growth periods than can be supplied through simple diffusion of "air derived" CO2 gas into the closed grow tent space? I believe that CO2 levels can be substantially depleted during intensive cannabis growth and without in/out tent airflow the rate of photosynthesis/transpiration declines.


Here is a good solid reference study regarding the CO2 depletion affect in semi-closed greenhouse spaces without sufficient intake/exhaust air flow:

Maximize photosynthesis with moving air

Covers subjects about horticulture and pest management for the grower and associated industries

ucanr.edu

 

[ppm Charlie]

Don't forget the magic of Fox Farm soil, maybe a tasty choice like some Happy Frog, assuming the Old Guy Teaches would approve.

I will try the FF and/or Happy Frog soil. Sounds good.