how many watts per Sq foot
- Thread starter DrFever
- Start date
grow_right
Member
if using low watts lamps, 150's and such, i used between 80 and 100 watts per sq ft. if using high watt lamps 400 and more, the average is about 60 to 75 watts per sq ft. you want to give as many watts per sq ft as possible before the plants get burnt, or suffer heat stress.
50-55wpsqft for 'average' densities with indica-dominant strains.
60-75wpsqft for higher density bud and more sativa-dominant strains.
I prefer the 60-75 as the buds go "thunk" on the tray... instead of 'Shushushush'. (I usually run sativa-dom hybrids).
Stay Safe!
60-75wpsqft for higher density bud and more sativa-dominant strains.
I prefer the 60-75 as the buds go "thunk" on the tray... instead of 'Shushushush'. (I usually run sativa-dom hybrids).
Stay Safe!
herbalistRoots
Active member
This was a useful formula reference I came across for that purpose. Hope it helps!
Grow Room Power Requirements Calculator
Q. How many lights do I need in my room?
A. For optimum lumens, you should have 20 (min) to 60 (max) watts per square foot.
Formula:
Square footage (length × width) of your room × 20 (wattage)
= The watts needed
Example:
10' (length) × 10' (width) × 20 (watts)
= 2,000 watts = 2 × 1,000 watt bulbs for that room
Input Values: All input values must be entered below to obtain results.
Number of lights you were thinking of adding Lights =
Wattage per light you were thinking of adding Watts =
Length of room (ft.) Length =
Width of room (ft.) Width =
Results
Total wattage
requirement
per square foot Watts/Sq. Ft. =
Optimum CO2 Calculator
Q. Why is it better to have more Cu.ft./hr. if using CO2?
A. The faster you achieve your desired CO2 levels the better. The room gets less heat (exhaust fan comes on faster) with higher Cu.ft. per hour of CO2.
Example:
A CD36 CO2 Generator achieves 50% faster CO2 then a CD18 Generator.
Input Values: All input values must be entered below to obtain results.
Length of Room (ft.) Length =
Height of Room (ft.) Height =
Width of Room (ft.) Width =
CO2 (ppm) (eg. for 1500ppm CO2 desired, use .0015 as the variable) Variable =
Time (seconds) * use 60 seconds for value Time =
Cu.ft. per hour of CO2 * value located on device Cu.ft./hr. =
Results
Total minutes CO2 has
to be on to reach optimum Total minutes =
Grow Room Power Requirements Calculator
Q. How many lights do I need in my room?
A. For optimum lumens, you should have 20 (min) to 60 (max) watts per square foot.
Formula:
Square footage (length × width) of your room × 20 (wattage)
= The watts needed
Example:
10' (length) × 10' (width) × 20 (watts)
= 2,000 watts = 2 × 1,000 watt bulbs for that room
Input Values: All input values must be entered below to obtain results.
Number of lights you were thinking of adding Lights =
Wattage per light you were thinking of adding Watts =
Length of room (ft.) Length =
Width of room (ft.) Width =
Results
Total wattage
requirement
per square foot Watts/Sq. Ft. =
Optimum CO2 Calculator
Q. Why is it better to have more Cu.ft./hr. if using CO2?
A. The faster you achieve your desired CO2 levels the better. The room gets less heat (exhaust fan comes on faster) with higher Cu.ft. per hour of CO2.
Example:
A CD36 CO2 Generator achieves 50% faster CO2 then a CD18 Generator.
Input Values: All input values must be entered below to obtain results.
Length of Room (ft.) Length =
Height of Room (ft.) Height =
Width of Room (ft.) Width =
CO2 (ppm) (eg. for 1500ppm CO2 desired, use .0015 as the variable) Variable =
Time (seconds) * use 60 seconds for value Time =
Cu.ft. per hour of CO2 * value located on device Cu.ft./hr. =
Results
Total minutes CO2 has
to be on to reach optimum Total minutes =
i like 60 to 75.
im running 62.5 w/sqft in my flower rooms,thats one 1000w lamp for every 4x4 space in my case,seems to work well,make sure your ventilation system is providing enough fresh air to keep up with that light density,a room full of plants can suck the air clean of co2 in a very short time..
reason i posted this thread is IMO as low as 40 can be optimal my last grow consisted of 5 x 8 =40 sq feet 2000 watts gave me 50 watts per Sq foot
5 plant = 4.75 pounds Dry more or less 15 0z dry per plant
i am starting to think that watts per Sq foot is important but having a complete dialed in room also makes 80 percent of a good grow as well
MY Next grow consists of 5 x 15= 75 Sq feet 3000 watts = 40 watts per
but doubling plant count and hoping for 150 oz dry
5 plant = 4.75 pounds Dry more or less 15 0z dry per plant
i am starting to think that watts per Sq foot is important but having a complete dialed in room also makes 80 percent of a good grow as well
MY Next grow consists of 5 x 15= 75 Sq feet 3000 watts = 40 watts per
but doubling plant count and hoping for 150 oz dry
what makes me happy is knowing the plants are getting maximum light an being all they can be. and great yields of rock solid buds... that too makes me happy .60 to 75 does this without overkill. my test tent runs at the max of 75. everything else is a bit less. back in the og days i had one parabolic setup that was 25 per and i did ok.i miss that strain.
So here is what stumps me. If you have a 5x5 scrog or sog under a 1000 watter in the middle of a 20x20 room, do you have 40psf or do you have 2.5psf?
Even tho you may have a 5 x 5 scrog in middle of a 20 x 20 room
Light are under reflector sending most of the lumens and wattage down into a specific area i am guessing if you placed plants further away from the source wattage declines so plants 10 feet away would be prob getting 2.5 + pending what you had for reflective wall material
You have 40wpsqft... approximately. With reflective surfaces on each side you would get a higher yield... but essentially you're at 40wpsqft. Just fine for more indica dominant strains.
Stay Safe!
T
TribalSeeds
This might not be the best place to ask, but Im wondering how to place my lights with so many of them over the plants. Im coming from growing in a tent and the lights had to be close. This grow Ive doubled my wattage(2400 now) and I think my lights are too close. I have them the same distance apart in a straight line, but I have two rows now. I think the reflectors on the two rows are only about 1ft-1.5 ft apart. They are hanging from my raptors and the next spot I can put them at would be 2 ft farther away.
Im getting light bleeching on my top buds if I have them any closer than 18" from the top of the cola. Should I be back about 2ft with so many lights? My canopy isnt very deep, but at 2ft I feel like Im not getting my 600's down in there very far, but even those buds have lightly bleached tops. Any suggestions?
Im getting light bleeching on my top buds if I have them any closer than 18" from the top of the cola. Should I be back about 2ft with so many lights? My canopy isnt very deep, but at 2ft I feel like Im not getting my 600's down in there very far, but even those buds have lightly bleached tops. Any suggestions?
i take it your running 600's ?????? 2 to 3 feet apart should work good if there on each side if there in a row then 1 - 2 foot apart is what i would do i run my 1000's 3 feet apart in a row with reflectors reflecting at each other so 1000's are shining on other plants that are under a 1000 and so on more or less over lapping each other
T
TribalSeeds
Yea, theyre all 600's. I have 2 of them about 1 ft apart per line, the second line is only about 2ft from the first though. Im actually using the same piece of duct I had set up in my tent. That was about as far apart as they could be seperated.
Id have to rig something up to the ceiling beams to be able to hang the hoods in the middle of a set of beams.
Would just raising the lights above the 18" be sufficient? Thats all Ive been able to do so far... I actually had them much closer before I added the second line. I notice most bigger grows the lights are like 2ft above, but usually those are 1000's.
Id have to rig something up to the ceiling beams to be able to hang the hoods in the middle of a set of beams.
Would just raising the lights above the 18" be sufficient? Thats all Ive been able to do so far... I actually had them much closer before I added the second line. I notice most bigger grows the lights are like 2ft above, but usually those are 1000's.
if a light explodes and nobody is around does it still make a pop?
Guido Sarducci
Member
This pdf is for "Adjust-A-Wing" reflectors but gives a general ideal regarding spacing/layout.
I've never used these reflectors so if anyone doesn't like them please direct your complaints elsewhere...
http://www.adjustawings.com/downloads/ajw_layout_tips_1.pdf
I've never used these reflectors so if anyone doesn't like them please direct your complaints elsewhere...
http://www.adjustawings.com/downloads/ajw_layout_tips_1.pdf
T
TribalSeeds
I just measured. There is 2ft between the edge of each reflector. If I were to put one line on the next beam over that would be 4ft between the lines.
My leaf isnt bleached, just the the tips of my colas. Is this a problem?
EDIT: I just found a simple solution. I took 2 bungee cords and managed to pull the lights to just under 3ft apart between lines. Im still at 2ft between reflectors in line though.
My leaf isnt bleached, just the the tips of my colas. Is this a problem?
EDIT: I just found a simple solution. I took 2 bungee cords and managed to pull the lights to just under 3ft apart between lines. Im still at 2ft between reflectors in line though.
that should work out good then i run my 1000's about 18" from tops you should be min that distance 600's lose allot of lumens as they go up from plant tops
