CFL heat output my limiting factor

The room/closet I'm currently working on is a secondary room to let two plants veg longer and see how much more of a yield I can get from them. Currently four girls are in a smaller/shorter space vegging, I'll split off two in a few weeks to this new space. Down the road I expect the first room will be for veg, and the new one for flowering so that I don't have to keep switching out the bulbs! But for this first grow, this will also serve to stagger the yields.

My initial misunderstanding (!!!) was that there was no such thing as too many CFL's, so I created as tightly packed and flat an array as I felt I safely could, in order to hang it inches over a SCRoG. There were 4x 42w and 8x 23w bulbs, for a total of about 350 watts. The "room" is a space partitioned off of half of a full sized closet, its interior dimensions are 22d x 28w x 72h. I have a 50cfm bathroom fan at the top to exchange air with the outside (i.e. the rest of the house - winter inside temps at 66), and a room fan inside to circulate air.

I decided to run the new room empty with the lights hanging about mid-way down, and see how the set up is working. I fired up the fans and lights and closed the doors, and in no time it was up around 90 degrees. I remembered that when I moved the girls from the 2" pots they came in (clones bought at a dispensary) to 10" pots, the small veg room they are in cooled down, so I wet a towel and spread it across the empty pots in front of the fan, to simulate the evaporative cooling having plants in there might provide… that took it down to about 87 degrees.

I increased the size of the passive air intake vent for better flow, and removed two of the 42w bulbs (and spread the others out a bit), and now its holding steady at 83 degrees. This will only work in the winter, we don't use A/C so when the room temps start to climb in the summer, I think this closet would cook.

This is my first grow, and it will be CFL's beginning to end. If I had been more patient and read more before I decided I had enough information to start, I might have gone a different route. In both closets I've set CFL's in a flat format, and both will be SCROGs. My biggest challenge has been heat! CFL's are surprisingly warm.

Any advice? Any such thing as a micro-swamp cooler, or other relatively small/passive low energy inexpensive ways of cooling the spaces down?

Looks to me like the board that your bulbs are mounted to is effectively preventing heat from rising and going out.
If you could make a bracket mounted to the back of your cabinet and eliminate the plywood that would help.
Also, try like I do-run your lights at night when it's cooler.
Try like 5PM to 10AM to veg, and maybe 8 to 8 during flower.
Also, are you measuring heat at light level or what will be your canopy level?

Bakatare666 said:

Looks to me like the board that your bulbs are mounted to is effectively preventing heat from rising and going out.
If you could make a bracket mounted to the back of your cabinet and eliminate the plywood that would help.
Also, try like I do-run your lights at night when it's cooler.
Try like 5PM to 10AM to veg, and maybe 8 to 8 during flower.
Also, are you measuring heat at light level or what will be your canopy level?

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Thanks for the feedback!

You might be right about the board I have the lights attached to. I cut off the back corners thinking I might run T-5's vertically in the back corners of the closet, and for now I thought those openings might be sufficient for air flow -- I have the fan at the top sucking air out and a large vent cut at the bottom for cool intake -- but there is probably a better solution than the board. I have a hole-saw, since its plywood, I could make "swiss cheese" out of it.

Currently I have the digital remote heat sensor hanging a few inches below the lights, at the top of the canopy level.

I may try to run it at night, it would mean during flowering all the doors would be closed to black it out during the day… hopefully that would be full 100% darkness… I suppose I could climb in there and have someone close me in to test it.

Humanrob said:

Thanks for the feedback!

You might be right about the board I have the lights attached to. I cut off the back corners thinking I might run T-5's vertically in the back corners of the closet, and for now I thought those openings might be sufficient for air flow -- I have the fan at the top sucking air out and a large vent cut at the bottom for cool intake -- but there is probably a better solution than the board. I have a hole-saw, since its plywood, I could make "swiss cheese" out of it.

Currently I have the digital remote heat sensor hanging a few inches below the lights, at the top of the canopy level.

I may try to run it at night, it would mean during flowering all the doors would be closed to black it out during the day… hopefully that would be full 100% darkness… I suppose I could climb in there and have someone close me in to test it.

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You could also add an intake fan if you have one, or even just a couple computer fans mounted by your intake to help push.
Don't laugh at the idea of climbing in bro..... I've heard of it done many times.
Even if you do have a couple gaps, some thin stick on foam insulation that comes in rolls easily seals door cracks and what not.

Bakatare666 said:

You could also add an intake fan if you have one, or even just a couple computer fans mounted by your intake to help push.
Don't laugh at the idea of climbing in bro..... I've heard of it done many times.
Even if you do have a couple gaps, some thin stick on foam insulation that comes in rolls easily seals door cracks and what not.

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The intake fan is an interesting idea, and I've already started patching cracks (so far all around the doors) with foam tape.

I've heard emphatically that the room MUST be 100% dark for 12 hours per day during flower, do you know what happens if light gets in?

Humanrob said:

The intake fan is an interesting idea, and I've already started patching cracks (so far all around the doors) with foam tape.

I've heard emphatically that the room MUST be 100% dark for 12 hours per day during flower, do you know what happens if light gets in?

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This is another subject like 'to flush or not to flush'.
Some say it MUST be 100%, others say that outdoors in the wild, 'what about the moon', so one could go either way.
I for one, don't really worry about it, as the moon theory kinda suits me.
Last year I built a quick half ass cardboard box so I could swap out my plants from light to dark.
I had 5 plants at once, and they all wouldn't fit in my space, so I took the smaller three together, and the larger two together, and would swap the space, leaving the lights on 24/7.
Some say if there is ANY light leaks, it will stress the plant, and possibly cause it to turn into a hermie.
Now, maybe I've just been lucky, not checking my closet nor box last year for leaks, but out of about 15 plants in 3 years in the closet, and 2 plants outdoors one year, I've not had an issue yet.
There ARE green CFL's that some guys use to play with their plants during lights out, but I've never invested the couple bucks for one......... I just pop in, do my thing and close the door behind me when I'm done.

We were going to do some outdoor plants this year, but we live in town and I just realized there are street lights all around us. I wonder if we'll even be able to grow them...

Humanrob said:

We were going to do some outdoor plants this year, but we live in town and I just realized there are street lights all around us. I wonder if we'll even be able to grow them...

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I remember a couple years ago a guy here had the same dilemma, but I never heard if or what came of it.
I don't even remember if he tried it just for an experiment or what, but the light in his case was right at the corner of his front yard.

Because the end of summer has some quick temperature changes here in Oregon, we often have to put up hoop houses and cover the outdoor girls at night so that they don't get covered with morning dew and get moldy. Usually we use clear plastic because it'll have a greenhouse effect and warm the plant up more quickly in the morning, but maybe I could do it with black plastic to help black-out the street lights. I suppose when I get closer I'll see if there is any info in the outdoor growing part of this site, so far everything for me has been indoor so that's what I've been focused on.

Bakatare666 said:

You could also add an intake fan if you have one, or even just a couple computer fans mounted by your intake to help push.
Don't laugh at the idea of climbing in bro..... I've heard of it done many times.
Even if you do have a couple gaps, some thin stick on foam insulation that comes in rolls easily seals door cracks and what not.

Click to expand...

I know it doesn't help you now but later if you go with the self build LED you can put the power supplies out side the box cuts way down on heat, also, I am very near you , and I was able to get my temps at 71 with an 6 inch fan

Oh and your box build looks great

Tim Fox said:

I know it doesn't help you now but later if you go with the self build LED you can put the power supplies out side the box cuts way down on heat, also, I am very near you , and I was able to get my temps at 71 with an 6 inch fan

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My next evolution will definitely be LED's, but for now I have a lot of time and money invested in these CFL's, so I'm going to use them, at least on this first crop.

With intake and exhaust fans running, the room seems like it will be cool enough to take me through one harvest, assuming we have a decently cool spring and I'm done by May.

Tim Fox said:

Oh and your box build looks great

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Thanks for that

the higher watt cfl get hotter at the ballast! your better off with the 23 waters and more of those. and those bathroom fans don't really get the job done imo, or maybe go to a higher cfm one. I used one in a closet with mass bulbs and it took some figuring out. trial and error brother, but your better off getting your room dialed in before you cook or kill your plants. you can check out my cfl grows down below

diamonddav said:

the higher watt cfl get hotter at the ballast! your better off with the 23 waters and more of those. and those bathroom fans don't really get the job done imo, or maybe go to a higher cfm one. I used one in a closet with mass bulbs and it took some figuring out. trial and error brother, but your better off getting your room dialed in before you cook or kill your plants. you can check out my cfl grows down below

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Yeah, that seems to be what I'm learning too.

An expensive lesson, since I spent a chunk of money on 40/42w bulbs. And the bathroom fan is kind of disappointing, but with the intake fan on the other side, it seems to be moving air through sufficiently.

We keep our house at 66 degrees in the winter, and what I've noticed is that the small room I have running stays at 10 degrees above room temp. When my aging parents came to visit and we bumped the thermostat up for them, the room temp in the closet rose almost exactly the same amount.

Bakatare666 said:

I remember a couple years ago a guy here had the same dilemma, but I never heard if or what came of it.
I don't even remember if he tried it just for an experiment or what, but the light in his case was right at the corner of his front yard.

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I've grown outdoors in town with 2 streetlights near my grow area and never had an issue, until some rat bastard ripped me :/

budlover13 said:

I've grown outdoors in town with 2 streetlights near my grow area and never had an issue, until some rat bastard ripped me :/

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I've lived on a couple of properties with outdoor grows, but both were miles from a town. Currently I live 100 yards from the Police Station, and my grow will be legal… this is uncharted territory for me! Very strange to think that my plants might not be taken because proximity to the Police will keep them safe.

By July it will be legal here for everyone, and I'm betting late August - early September, the smell of ripening buds will be in the air everywhere. That'll be a bit surreal, but I am looking forward to it.

diamonddav said:

you can check out my cfl grows down below

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I did check out your threads, interesting reads. I think the human brain, when faced with conflicting information, has a tendency to filter for information that meets its expectations… I've been trying to figure out how in all of my research I missed so much. Since there is a LOT of contradictory information out there, the brain has to sift and sort, it can't all be right so at some point we choose -- we filter out one set of opinions and focus on the other.

I saw (at least) one great thread by someone who had healthy yields from CFL's, read a bunch by people who love them, and that was what I wanted to hear and I went out and created a CFL set up. Supposedly inexpensive, runs cool (not hot), and done right can produce substantial robust plants.

Then I kept reading. As soon as I started to have issues with mine, all of a sudden I'm seeing all kinds of threads with people finding the limitations of CFL's -- all the info I was filtering out because it seemed like both opposing views could not be simultaneously correct. My monkey brain just could not process it all on the first pass. I think now I'm starting to see the whole picture better.

In the end there are a million shades of grey, and it all depends on a persons expectations and needs. I'm still very early in the learning curve, but with my girls at only a few weeks into veg, I already know how I'll do things differently next time. Since it looks like I'll be moving the next batch outside for the summer, it'll be next fall before I get to try Version 2.0 of my grow rooms.

You tell them ,I feel like shouting it from the rooftop's, legal to grow in our amazing state of Oregon!!!

Humanrob said:

I've lived on a couple of properties with outdoor grows, but both were miles from a town. Currently I live 100 yards from the Police Station, and my grow will be legal… this is uncharted territory for me! Very strange to think that my plants might not be taken because proximity to the Police will keep them safe.

By July it will be legal here for everyone, and I'm betting late August - early September, the smell of ripening buds will be in the air everywhere. That'll be bit surreal, but I am looking forward to it.

Click to expand...

Tim Fox said:

You tell them ,I feel like shouting it from the rooftop's, legal to grow in our amazing state of Oregon!!!

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Oregonians organized and showed up at the polls! The people have spoken!

But its not over yet, I'm hearing talk of the legislature making changes to the law, after it was voted on. It'll be an interesting ride. I'm in a pretty conservative small town, I'm waiting to see how the local police actually react. Since the new law does not officially take affect until July 1st, anyone discovered with plants in the ground in June is subject to the current laws. At the county level my understanding is the DA publicly said he will no longer prosecute based on the old laws, but I don't know that each city jurisdiction will react the same way. Luckily my house is OMMP, so we're covered either way -- but this is one of those laws that had strong opposition and will not necessarily be enacted smoothly or consistently.

That said, as it stands it definitely feels good.