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how light is too much
- Thread starter foo_bird
- Start date
E
EvilTwin
I actually don't have any experience with high intensity grows. I shoot for around 65 watts/SF in my garden.
Having the light intensity that bright increases demands on the plant (and your room). You have to bump up the nutrients and deal with the increased heat production. Best if you use CO2 as well.
But in tiny micro-grows...it's sometimes hard to get the intensity right where you want it. So those are the places you generally see high light intensities. High tech, sealed room, CO2 with cooled lights and a tweaked hydro system...and micro-grows. I'd say dial it down to a more managable level personally.
ET
what light do you have? planning to get a light? shoot for 40-75 a square foot general rule
one way to increase light is getting the light as close as possible, low temps help with this
don't worry to much, once the plant gets it roots, its not as important to have a high high light, well that's for veg anyways.. the people I value the highest seem to use floros for veg if that's any clue
one way to increase light is getting the light as close as possible, low temps help with this
don't worry to much, once the plant gets it roots, its not as important to have a high high light, well that's for veg anyways.. the people I value the highest seem to use floros for veg if that's any clue
darookie2000
Member
If the tips of your plants start turning white, you've got too much light. Other than that, the more the better (for healthy, mature plants - more light is better during flower - enough light is fine during veg), PROVIDED, you can keep it cool enough.
i've had light intensity issues where temps/rh/co2 have all been in check... some strains are more prone than others... it looks like your lights are too close and your plants are overwatered a bit but your lights can be pretty far away and the medium can be pretty normal.... previously i'd have to raise the lights 30"s above the canopy but i was stacking 3 600s with super sun 2 reflectors and ushio bulbs on digital ballasts in like a 4x5 space; really was too many lumens... it seems that the strain i had, soma rockbud, was especially sensitive to the light intensity issues as well which didn't help... i had two 1000's in the same space and had the same issues... i ended up raising the lights so high i figured it was just better off running 600s slammed as low as possible... can get them 12-16" inches off the canopy now with no ill effects.. only running 2 over a 3x6 in radiant6 reflectors; makes for a nice solid canopy... but yeah... i think there is a lot to be said for the difference in lumen output between old mag ballasts, old bulbs, and old reflectors vs digital ballasts, new bulbs, and new reflectors that people don't take into account when making recommendations.... also light movers let you run your lights was closer to the canopy allowing for deeper penetration without burning the tops
i think my problem was compounded by surrounding the cab with panda plastic which just increased the lumens intensity even higher... sometimes too much of a good thing can really be too much
i think my problem was compounded by surrounding the cab with panda plastic which just increased the lumens intensity even higher... sometimes too much of a good thing can really be too much
BLUNToPOTomuss
Member
Im running 100w/10,000 Lumens a sqft and it is perfect!
a 400 watt HPS cooltubed in a 16 cusqft cab. I can grow the plants around the glass it stays so cool!
If you can keep the enviro cool there is no reason to worry about to much light.
of course there are extreme occasions but none the less no need to worry.
a 400 watt HPS cooltubed in a 16 cusqft cab. I can grow the plants around the glass it stays so cool!
If you can keep the enviro cool there is no reason to worry about to much light.
of course there are extreme occasions but none the less no need to worry.
Fluoro's - Don't provide an intense enough light to penetrate plant canopys so if a small/micro SCRoG where the light pattern is equal to the floorspace ie; a 2' x 2' area uses 2' long fluoro's and enough of them to cover the 2' depth of the grow aswell).
Small H.I.D.s (70w-250w) provide a more intense light allowing for some plant canopy penetration.
400w HPS - Has a 50k - 55k total lumen rating and can penetrate a plants canopy down about 1.5'-2'.
600w HPS - Has a 90k total lumen rating and can penetrate plant canopies 2'-3'.
1000w HPS - Has a 140k-145k total lumen rating and can penetrate the plants canopy about 4'.
I use a 400w HPS in an air-cooled hood,hung in a 2.5' w x 2' d C13 cab.This allows for 10k lumens per square foot,and 80w per square foot.
General minimal rule of thumb is 50wpsf and about 6500-7000lpsf
I have personally never gone any more intense to say like 100wpsf and 12k+ lpsf but I think after 10k lumens per square foot you might get some bleaching or diminishing returns.
Like other have said,when cranking up the wpsf or lpsf,it also cranks the heat and radiant heat up inside the grow so unless you have proper ambient temps and sufficient airflow,proper size/number of intakes and you try to dump your exhuast air into the attic,out a window via window exhuast box,or to another room.
For exhuast fans,multply the size of your grow space to find out how many cubic feet your grow space is (w x l x h = cubic feet).Now multiply the cubic volume of your grow space and mutliply that by 3 or 5.That is the minimum cfm fan you should need but there are many many variables like what your ambient temps are/will be,if or not you can dump all exhuast air to another area other then the room your growspace will be in because just dumping hot exhuast air in the room the grow space sits in just raises the ambient temps which raises the grow spaces temps,if you will be using one fan for an area,if you will be using one fan for cooling of the light and ventilating the area,if you'll be using a carbon filter,if you'll be using two fans one to cool the the light the other to ventilate and clean air via carbon scrubber etc. etc. etc.
There is no one simple answer becuase of all these variables.
Given that your ambient temps are in a reasonable range,you have sufficient airflow,you shold have no problem doing 70wpsf.
For any help with exhuast fans,ventilation,cab/grow cooling I would strongly advise you take a look at these links:
How Do I Design A Fan Powered Cooling System For My Growbox
Ventilation 101
How Do I Intall A Duct Fan To Operate Most Efficiently
Two of the best fans IMO that many growers use are inline centrifugal exhuast fans (Vortex,Eco Plus,Can Fan,Elicent,Fantech) and inline mixed vent exhuast fans (Soler & Palau).
Inline centrifugal exhuast fans are loud,but they move alot of air,especially in environment with high static pressure mixed in the equation (static pressure/duct losses occur anytime we add something to the fan wether it be ducting,an air-cooled reflector,a carbon filter of any kind,shape,or size etc.).
There are a few threads where I have mentioned that I like to compare all fans to the ones made by Can Fan,only because Can Fan gives us the technical specs. of each fan ie; it's cfm/airflow ratings from 0" static pressure to the max. amount of static pressure the fan can still move air at,also they state the max wattag,RPMs,etc.
Soler & Palau do the same thing and if we compare a Can Fan 6"HO exhuast fan to an S&P TD-150 we see that they are not too different in specs.They both handle some static pressures (Can Fan 6"HO being the winner),but the S&P uses way less power.
Here is a chart of the Can Fans specs. and a chart of the S&P specs. -
Can Fan Chart
Soler & Palau Spec. Chart
Also I like to use the Can Fans and Can Filters when comparing fans and carbon filters.I like to use the Can Fan 6"HO and the Can Filter 50.
Again on the Can Fan wbesite we see that each filter has maximum airflow/cfm ratings for pulling air through the filter or pushing/exhuasting into the filter.Do not use a fan that exceeds those ratings.They also state the minimum airflow/cfm fan rating to be used with the filters.
We see at the Can Fan wevsite that usign a Can Fan 6"HO with a Can Filter 50 that the airflow would be reduced from 392cfm (the can fan 6:HO's free air airflow rating) to 300cfm,therefore attaching the filter to the fan increases static pressure from 0" to .5"...compare to the can fan chart above.
Now we look at the S&P spec. chart...
If we compare the TD-150 (at full power/high speed) with the Can Filter 50 we see that at .5" static pressure the S&P TD-150 has an airflow/cfm rating of 206cfm (that's only 94cfm less airflow then the Can Fan 6"HO).
There are many variable,to reitterate,but with all that mumbo-jumbo ^ and the links I gave you,you should have more then enough info to make a knowledgeable decision on what fan you'll need in order to keep your grow space cool/well ventilated and odorless with a high wpsf environment.
Severely stoned ramble,over.
Small H.I.D.s (70w-250w) provide a more intense light allowing for some plant canopy penetration.
400w HPS - Has a 50k - 55k total lumen rating and can penetrate a plants canopy down about 1.5'-2'.
600w HPS - Has a 90k total lumen rating and can penetrate plant canopies 2'-3'.
1000w HPS - Has a 140k-145k total lumen rating and can penetrate the plants canopy about 4'.
I use a 400w HPS in an air-cooled hood,hung in a 2.5' w x 2' d C13 cab.This allows for 10k lumens per square foot,and 80w per square foot.
General minimal rule of thumb is 50wpsf and about 6500-7000lpsf
I have personally never gone any more intense to say like 100wpsf and 12k+ lpsf but I think after 10k lumens per square foot you might get some bleaching or diminishing returns.
Like other have said,when cranking up the wpsf or lpsf,it also cranks the heat and radiant heat up inside the grow so unless you have proper ambient temps and sufficient airflow,proper size/number of intakes and you try to dump your exhuast air into the attic,out a window via window exhuast box,or to another room.
For exhuast fans,multply the size of your grow space to find out how many cubic feet your grow space is (w x l x h = cubic feet).Now multiply the cubic volume of your grow space and mutliply that by 3 or 5.That is the minimum cfm fan you should need but there are many many variables like what your ambient temps are/will be,if or not you can dump all exhuast air to another area other then the room your growspace will be in because just dumping hot exhuast air in the room the grow space sits in just raises the ambient temps which raises the grow spaces temps,if you will be using one fan for an area,if you will be using one fan for cooling of the light and ventilating the area,if you'll be using a carbon filter,if you'll be using two fans one to cool the the light the other to ventilate and clean air via carbon scrubber etc. etc. etc.
There is no one simple answer becuase of all these variables.
Given that your ambient temps are in a reasonable range,you have sufficient airflow,you shold have no problem doing 70wpsf.
For any help with exhuast fans,ventilation,cab/grow cooling I would strongly advise you take a look at these links:
How Do I Design A Fan Powered Cooling System For My Growbox
Ventilation 101
How Do I Intall A Duct Fan To Operate Most Efficiently
Two of the best fans IMO that many growers use are inline centrifugal exhuast fans (Vortex,Eco Plus,Can Fan,Elicent,Fantech) and inline mixed vent exhuast fans (Soler & Palau).
Inline centrifugal exhuast fans are loud,but they move alot of air,especially in environment with high static pressure mixed in the equation (static pressure/duct losses occur anytime we add something to the fan wether it be ducting,an air-cooled reflector,a carbon filter of any kind,shape,or size etc.).
There are a few threads where I have mentioned that I like to compare all fans to the ones made by Can Fan,only because Can Fan gives us the technical specs. of each fan ie; it's cfm/airflow ratings from 0" static pressure to the max. amount of static pressure the fan can still move air at,also they state the max wattag,RPMs,etc.
Soler & Palau do the same thing and if we compare a Can Fan 6"HO exhuast fan to an S&P TD-150 we see that they are not too different in specs.They both handle some static pressures (Can Fan 6"HO being the winner),but the S&P uses way less power.
Here is a chart of the Can Fans specs. and a chart of the S&P specs. -
Can Fan Chart
Soler & Palau Spec. Chart
Also I like to use the Can Fans and Can Filters when comparing fans and carbon filters.I like to use the Can Fan 6"HO and the Can Filter 50.
Again on the Can Fan wbesite we see that each filter has maximum airflow/cfm ratings for pulling air through the filter or pushing/exhuasting into the filter.Do not use a fan that exceeds those ratings.They also state the minimum airflow/cfm fan rating to be used with the filters.
We see at the Can Fan wevsite that usign a Can Fan 6"HO with a Can Filter 50 that the airflow would be reduced from 392cfm (the can fan 6:HO's free air airflow rating) to 300cfm,therefore attaching the filter to the fan increases static pressure from 0" to .5"...compare to the can fan chart above.
Now we look at the S&P spec. chart...
If we compare the TD-150 (at full power/high speed) with the Can Filter 50 we see that at .5" static pressure the S&P TD-150 has an airflow/cfm rating of 206cfm (that's only 94cfm less airflow then the Can Fan 6"HO).
There are many variable,to reitterate,but with all that mumbo-jumbo ^ and the links I gave you,you should have more then enough info to make a knowledgeable decision on what fan you'll need in order to keep your grow space cool/well ventilated and odorless with a high wpsf environment.
Severely stoned ramble,over.
+rep and quote for important info clearly explained. That is exactly how I matched up an S&P fan with a Can Filter, with some educated guessing about additional static pressure imposed by the air flow path in my design.
