first grow, co2/ventilation questions

messedup

Member
Hi there, my first post about my first grow :)

I have attached a rough sketch of my home made grow box, it has 1 intake (large server fan, lots of air movement) and 2 out take (1 large fan again, 1 standard case fan). The idea being this would cover both ventilation and air movement. All holes are going to be scrubbed/carbon filtered.

The thing is this will mean any co2 I can get in there will quickly be lost... which isnt what I want. I dont think I need the ventilation because im only using 250w CFL light which gives off very little heat.

Appart from the ventilation holes the unit is pretty much air tight, and the whole interior is lined with mylar (mylon?)

Would it be worth plugging the holes where the fans are, leaving the fans in for air movement but cutting off ventilation so that I can keep co2 levels more constant?

Im planning a scrog grow with 5-6 plants.

Any info/ideas more than welcome.

Thanks.
 

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Phenom420

Well-Known Member
Sounds like your gonna need more light than that.
I use a shit load of CFLs and a 250w won't b enuf on it's own.
 

messedup

Member
Im toying with the idea of LST instead of scrog due to being able to manage each plant individually (wouldnt want to have to mess around un scrogging males etc). Which grow would suit my grow box more?
 

messedup

Member
More light, not a problem. The light I have is pretty big and takes up alot of the space available (bulb is 12"-14" long). Can easily add some smaller cfls, which I will do, thanks for the advice :).
 

Phenom420

Well-Known Member
The light is 250W 8U CFL 6400k
ahh that will work just fine for veg, well the color, you will need to ad more, it will handle the seedling and about 2-3 weeks later you will wind up having to upgrade or they wont grow nearly as fast.

It's a never ending clib for me, I have to buy more lights every week.bongsmilie
 

cowell

Well-Known Member
Hi there, my first post about my first grow :)

I have attached a rough sketch of my home made grow box, it has 1 intake (large server fan, lots of air movement) and 2 out take (1 large fan again, 1 standard case fan). The idea being this would cover both ventilation and air movement. All holes are going to be scrubbed/carbon filtered.

The thing is this will mean any co2 I can get in there will quickly be lost... which isnt what I want. I dont think I need the ventilation because im only using 250w CFL light which gives off very little heat.

Appart from the ventilation holes the unit is pretty much air tight, and the whole interior is lined with mylar (mylon?)

Would it be worth plugging the holes where the fans are, leaving the fans in for air movement but cutting off ventilation so that I can keep co2 levels more constant?

Im planning a scrog grow with 5-6 plants.

Any info/ideas more than welcome.

Thanks.
Hook your fans and co2 up to a timer, turn the co2 on for 15 minutes every 3 hours or whatever, and run your fans to shut off during that 15 minutes. It's a pretty standard practice from the guys I talk to.
 

messedup

Member
:D

Thanks for the quick replies I genuinely really appreciate it as im a bit of a perfectionist and nagging issues drive me mad :D

Im doing the grow with my brother and we have decided were going to purchase another light, maybe a 400w HPS if my box can take the heat, if not can always improvise my vents. So this light SHOULD make do for the next few weeks :).

Im trying to find the memory card for my phone so I can upload some pics as id like your opinion on the current ventilation setup. The server fans that are in there are really powerful for their size and the airflow in there is nice, how do you personally keep the co2 levels in check?

Again, many thanks +rep
 

messedup

Member
Hook your fans and co2 up to a timer, turn the co2 on for 15 minutes every 3 hours or whatever, and run your fans to shut off during that 15 minutes. It's a pretty standard practice from the guys I talk to.
Awesome idea, nice and simple!

So that 15 minutes of co2 daily is enough for the plants then?
 

jcdws602

Well-Known Member
If you purchase a 400 watt consider buying an air-cooled hood if you think heat will be an issue.If you want juicy dense nugz = ] HID is the way to go.
 

cowell

Well-Known Member
Awesome idea, nice and simple!

So that 15 minutes of co2 daily is enough for the plants then?
No sorry bro, I should have been more specific on that..

For 15 minutes every like 3-4 hours from what I understand... check out "I grow Chronic" on UTUBE, the guy goes through a set up for a grow room, and he also brings up the CO2 on a timer and mentions the on/off time for it on there to be sure...

If you haven't ever watched it, it's worth the hour and a half of your time.. roll a few fatties and smoke while you watch, it's fairly basic, but gives you a good idea of things and where to go from there is up to your research.:peace:

And I would think that 15 minutes per day wouldn't do enough benefit to bother even in a closet grow.. I could be totally off on that, but I don't think so...someone correct me if I'm wrong please.
 

Phenom420

Well-Known Member
Hey HPS isnt good for veg, they are awesome for flower but for veg you need some 6500-5500k range lights, MH or CFLs work great.
 

jcdws602

Well-Known Member
No sorry bro, I should have been more specific on that..

For 15 minutes every like 3-4 hours from what I understand... check out "I grow Chronic" on UTUBE, the guy goes through a set up for a grow room, and he also brings up the CO2 on a timer and mentions the on/off time for it on there to be sure...

If you haven't ever watched it, it's worth the hour and a half of your time.. roll a few fatties and smoke while you watch, it's fairly basic, but gives you a good idea of things and where to go from there is up to your research.:peace:

And I would think that 15 minutes per day wouldn't do enough benefit to bother even in a closet grow.. I could be totally off on that, but I don't think so...someone correct me if I'm wrong please.

It depends how big your area is,I know I run Co2.1500 ppm is ideal.The best way to monitor Co2 is with a Co2 controller
 

messedup

Member
Im not sure how to calculate the volume, but its about 4' wide 3.5' deep and 4' tall, smaller than I remembered actually just measured it up. Thats roughly, 12 sq ft? I know its quite a small box which is why im looking at lst/scrog.

EDIT: what kind of results can I expect if I dont do anything with co2 and just try to breath into the box alot? :P

2nd EDIT: im thinking of making a yeast/sugar solution in a few 2l coke bottles, with a few of these in the box would it be enough co2 produced to keep up with the amount of air being replaced and keep co2 at an acceptable level for the plants? Has anyone used co2 tabs in their soil with decent results or does the co2 need to be around the leaves for photosynthesis?
 

cowell

Well-Known Member
It depends how big your area is.
It depends how big your area is,I know I run Co2.1500 ppm is ideal.The best way to monitor Co2 is with an Co2 controller
Very correct info. I was speaking on a very base level though... If you can get away with controlling your temps without HAVING to run the fans all the time, then that would be a great set up for you too.I know it's not the best possible solution to accurately monitor your CO2 by setting fans on timers, but it's foolproof, and better than nothing, and if you are running air exchange every minute.. you just shoot your CO2 out the exhaust anyway right?

Just trying to help, BUT if I'm wrong on it, I can accept that and learn from it but common sence has served me well over the years.. and it tells me - I can shoot CO2 that's continually vented all day long, or run it for a few minutes a day and save $ and still benefit.

I'm not saying it's the "best" way of doing it, I'm just cheap.. home brew in the grow room kinda cheap! (just kidding... or am I?)
 
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