How Much Ventilation Do I Need in My Grow Room?

[Skybound]

Sorry, but I am a DIY guy and I do encourage people to try their hands at DIY stuff as your skills WILL develop also with practice, and you WILL get more in tuned with your growing environment. HERE is my DIY CFL reflector that did me very well for the time that I used it, but I have a lot more equipment now and was able to discontinue using it. If you want, you can mod my design by keeping the core electrical components and bulbs, and just not use the wood or aluminum. You can likely tear apart a cereal box and line a side with aluminum tape, then tape that new reflector to the power strip in such a way to reflect max lumens in the direction you desire. I do wish to advise also using zip ties to secure the socket splitters to the power strip as they did fall out on me prior to building that rig.

Here's my deal with LEDs. I have yet to use one myself, but I am subbed to quite a few journals and some that use LEDs and I am seeing them produce just as well as HID when they are able to stay at 18 inches above the canopy, but once the plants live up to their nature and just keep growing beyond our desired heights, the LEDs greatly lose their efficiency as the required angles needed to create even color coverage is lost. Not to mention that LEDs will bleach the leaves if they get too close. Given the height of your box, you would at least be best served if you carried a nice CFL backup for when your plants overtake the LEDs needed buffer zone, your grow doesn't suffer from light bleaching and improper color distribution.

To summarize, getting the LED will be an asset no doubt, but in your current setup, it will only have limited use IMO. But I know once you start kicking out loads of dank, you're only gonna want more like the rest of us and start looking for ways to grow in a bigger spot and having that LED panel will be nice at that time. Just be prepared to supplement if/when the grow exceeds your expectations.

 

[FiveToMidnight]

Sorry, but I am a DIY guy and I do encourage people to try their hands at DIY stuff as your skills WILL develop also with practice, and you WILL get more in tuned with your growing environment. HERE is my DIY CFL reflector that did me very well for the time that I used it, but I have a lot more equipment now and was able to discontinue using it. If you want, you can mod my design by keeping the core electrical components and bulbs, and just not use the wood or aluminum. You can likely tear apart a cereal box and line a side with aluminum tape, then tape that new reflector to the power strip in such a way to reflect max lumens in the direction you desire. I do wish to advise also using zip ties to secure the socket splitters to the power strip as they did fall out on me prior to building that rig.

Here's my deal with LEDs. I have yet to use one myself, but I am subbed to quite a few journals and some that use LEDs and I am seeing them produce just as well as HID when they are able to stay at 18 inches above the canopy, but once the plants live up to their nature and just keep growing beyond our desired heights, the LEDs greatly lose their efficiency as the required angles needed to create even color coverage is lost. Not to mention that LEDs will bleach the leaves if they get too close. Given the height of your box, you would at least be best served if you carried a nice CFL backup for when your plants overtake the LEDs needed buffer zone, your grow doesn't suffer from light bleaching and improper color distribution.

To summarize, getting the LED will be an asset no doubt, but in your current setup, it will only have limited use IMO. But I know once you start kicking out loads of dank, you're only gonna want more like the rest of us and start looking for ways to grow in a bigger spot and having that LED panel will be nice at that time. Just be prepared to supplement if/when the grow exceeds your expectations.

Please do not apologise, I WISH I could do DIY like yourself, it would save me so much money! Unfortunately I have never had much of a feel for DIY. I have tried many times but always seem to make mistakes. Can't seem to measure properly or cut straight! hahahaha

That CFL reflector looks awesome, however your idea of swapping the wood and aluminium for cardboard lined with aluminium tape or possibly Mylar sounds more in my skillset. I really like your design and think I might look at something very similar.
Would I still need to think about placing CFL's on the sides or towards the bottom of the box once the plants started growing or would being above the plants be enough? I have seen quite a few journals where they have used CFL's and seem to have them everywhere.

I also like what you have said about LED's and I think I may go with purchasing the MarsHydro model to start with and if the plants get too big, swapping it for CFL's. As you say, I'm sure I will be looking to expand in the near future.

 

[Skybound]

CFLs are great for those on a budget, can't spare power usage, or only have a very small space to work with. However, they do not give off the same intensity of light as that of LED or HID which is why growers first choose them. With that said, you would want to keep your CFLs about a foot above the canopy, but there is much less worry if your canopy overtakes the CFLs because they don't burn that hot and their weakness of intensity deters them from bleaching your leaves. If you are growing in soil, it is likely that you will get a bit more time to make needed adjustments as soil grows are somewhat slower in terms of stretching and branching out.

Back to your initial question(s) of ventilation. What do you have planned in terms of inlet and exhaust holes? How will new air come in and old air get removed?

 

[FiveToMidnight]

CFLs are great for those on a budget, can't spare power usage, or only have a very small space to work with. However, they do not give off the same intensity of light as that of LED or HID which is why growers first choose them. With that said, you would want to keep your CFLs about a foot above the canopy, but there is much less worry if your canopy overtakes the CFLs because they don't burn that hot and their weakness of intensity deters them from bleaching your leaves. If you are growing in soil, it is likely that you will get a bit more time to make needed adjustments as soil grows are somewhat slower in terms of stretching and branching out.

Back to your initial question(s) of ventilation. What do you have planned in terms of inlet and exhaust holes? How will new air come in and old air get removed?

Its funny, it seems they are good for people on a budget that are not in Aus. I'm finding to get 2-4 CFL's is the same price as the LED I am looking at.
I'm really thinking of still getting the LED and swapping to CFL's if the plant gets too big. I'm just wondering if swapping the lights halfway through would have a detrimental effect or not?
I am looking to use a soiless medium like Coco Coir due to being quicker than soil.

I have had a few people that have done similar size grows advise that PC fans are not going to be powerful enough to do the job so I was pushed towards something more like this

or

with this

and one of these (cheaper though)

What do you think?
I was also advised it may be a good idea to have a small desk fan inside the box for air movement

 

[Skybound]

Sorry to keep hitting back to my DIY stuff, but HERE I took the vital parts from my 400 watt HID air cooled hood and built my own air cooled hood, though much more compact as I was growing in a small closet. Aside from the DIY aspect, please take note that I also used a PC fan to cool the 400 watt HPS bulb, and suck off whatever air happened to waft near the bulb. The fan is a 120mm PC fan that is only 110 CFM. I found it to be on the loud side, but it did keep the grow area very manageable as inlet air came in from the bottom of my cabinet that was elevated off the floor and we know the coolest air is in the lowest point of the room.

If CFLs are expensive there, consider regular fluorescent lighting.

Aside from my fear of you bleaching your leaves, I should have prefaced with asking the age of the plants being put into bloom are? If you veg them for only 3-4 weeks, your LEDs might not get over ran so to speak. My mistake was not to first consider that I like to veg my plants for 4+ months which makes them very bushy and just large. So when bloom sets in and they stretch immensely more than that, I understand the problem of things getting out of control and space becoming a concern. If you start bloom sooner though as most growers do, you will find that because the starting plant was much smaller, when the bloom stretch occurs, your grow space will still likely be in good shape, thus making your LED more efficient. In my defense though, this is a cannabis growing website and one can assume that I stay medicated for much of my day.

At any rate, I think you'll be fine if you don't veg for too long, but if you do, keep a backup plan on standby.

Inlet air from low, exhaust it out high and do not let any light escape or this might cause hermis to show up which you do not want. I do use simple mazes created with wall studs, but cardboard taped to create the same design will work just fine, just keep all light from penetrating in. Yes, do get some small fans, oscillating if available. If you can't get a small enough oscillating fan, a regular small fan will suffice, just aim the air flow at a side wall, to the reflected air creates something of a spiral in the case. This is just to keep a constant flow of new air and CO2 across the leaves and also help perspiration, especially during bloom.

 

[FiveToMidnight]

Sorry to keep hitting back to my DIY stuff, but HERE I took the vital parts from my 400 watt HID air cooled hood and built my own air cooled hood, though much more compact as I was growing in a small closet. Aside from the DIY aspect, please take note that I also used a PC fan to cool the 400 watt HPS bulb, and suck off whatever air happened to waft near the bulb. The fan is a 120mm PC fan that is only 110 CFM. I found it to be on the loud side, but it did keep the grow area very manageable as inlet air came in from the bottom of my cabinet that was elevated off the floor and we know the coolest air is in the lowest point of the room.

If CFLs are expensive there, consider regular fluorescent lighting.

Aside from my fear of you bleaching your leaves, I should have prefaced with asking the age of the plants being put into bloom are? If you veg them for only 3-4 weeks, your LEDs might not get over ran so to speak. My mistake was not to first consider that I like to veg my plants for 4+ months which makes them very bushy and just large. So when bloom sets in and they stretch immensely more than that, I understand the problem of things getting out of control and space becoming a concern. If you start bloom sooner though as most growers do, you will find that because the starting plant was much smaller, when the bloom stretch occurs, your grow space will still likely be in good shape, thus making your LED more efficient. In my defense though, this is a cannabis growing website and one can assume that I stay medicated for much of my day.

At any rate, I think you'll be fine if you don't veg for too long, but if you do, keep a backup plan on standby.

Inlet air from low, exhaust it out high and do not let any light escape or this might cause hermis to show up which you do not want. I do use simple mazes created with wall studs, but cardboard taped to create the same design will work just fine, just keep all light from penetrating in. Yes, do get some small fans, oscillating if available. If you can't get a small enough oscillating fan, a regular small fan will suffice, just aim the air flow at a side wall, to the reflected air creates something of a spiral in the case. This is just to keep a constant flow of new air and CO2 across the leaves and also help perspiration, especially during bloom.

To be honest, your DIY stuff has given me all the ideas I have so far, it's been really helpful!

I haven't started the grow yet, but I can't imagine I would have them veging for around 3-6 weeks, depending on what seemed right at the time and what advice I was getting. I'm starting with Northern Lights Feminised which has a short flowering period, although I'm not sure if that means anything when it comes to veg stage lol.
I would love to have a huge plant or 7 but unfortunately due to room and legal situation, I have to keep it small. I also like to stay medicated for most of the day haha

From what I understand, I should be able to judge when they are about 40% the height of the space, at which time I figure I will be switching it to flower, so we should be all good with LED. However I always try to have a backup plan in place just in case.

I will be using this in an almost straight line setup I think

100mm

Plus I was looking to make a passive intake from PVC elbows similar to the one you showed me earlier.

What do you think?

Also, sorry for the late reply, been away with work

 

[Skybound]

I like, I like! Though you should further research the genetics of Northern Lights and see what the Sativa percentages are. Sativas have a tendency to grow very tall, some more than others, and if NL is high in Sativa, you might want to decrease 40% down to like 30% of space.

Also, when you upgrade to a bigger grow room, the 4" equipment will be harder to use. For this reason I myself switch to buying at least 6" fans and such. For the record, I use the same exact style fan you have linked and they work fine. They might not push/pull as strong as the Vortex styled fans, but a single fan was enough to move the heat off two of my 600 watt HIDs efficiently.

 

[FiveToMidnight]

I like, I like! Though you should further research the genetics of Northern Lights and see what the Sativa percentages are. Sativas have a tendency to grow very tall, some more than others, and if NL is high in Sativa, you might want to decrease 40% down to like 30% of space.

Also, when you upgrade to a bigger grow room, the 4" equipment will be harder to use. For this reason I myself switch to buying at least 6" fans and such. For the record, I use the same exact style fan you have linked and they work fine. They might not push/pull as strong as the Vortex styled fans, but a single fan was enough to move the heat off two of my 600 watt HIDs efficiently.

I picked Northern Lights as it was highly recommended for first time growers. It has a very short flowering period and is a short growing plant so I think it should be ok. We'll see what happens anyway.

I think it's more a question of IF I will upgrade to bigger instead of WHEN. lack of space and stealth being the number one requirement means this will be as big as I can go for quite a while. But I get what you mean about the fan size. I was thinking more about trying to take the least amount of space possible so I have more room for lights and plant growth. Due to the depth of the box, the lights will have to sit underneath the fan so I'm looking to make it as small as possible

 

[xhaze956x]

All ur plants should be dancing. Not bending. If thats happening ur good

 

[FiveToMidnight]

I like, I like! Though you should further research the genetics of Northern Lights and see what the Sativa percentages are. Sativas have a tendency to grow very tall, some more than others, and if NL is high in Sativa, you might want to decrease 40% down to like 30% of space.

Also, when you upgrade to a bigger grow room, the 4" equipment will be harder to use. For this reason I myself switch to buying at least 6" fans and such. For the record, I use the same exact style fan you have linked and they work fine. They might not push/pull as strong as the Vortex styled fans, but a single fan was enough to move the heat off two of my 600 watt HIDs efficiently.

All ur plants should be dancing. Not bending. If thats happening ur good

So with this 4" fan I showed above, how big do you think I should be making the passive intake?

 

[Skybound]

Your inlet is going to be flexible in that you can play around with how much air you allow in. The more air flow, the less restriction and your fan wont have to work as hard. Also, you're not obligated to draw from a single point so you can opt for a series of smaller holes in a configuration that best works for the enclosure.

 

[FiveToMidnight]

Your inlet is going to be flexible in that you can play around with how much air you allow in. The more air flow, the less restriction and your fan wont have to work as hard. Also, you're not obligated to draw from a single point so you can opt for a series of smaller holes in a configuration that best works for the enclosure.

Would you have any suggestion as to how best to do this with my setup?

 

[Skybound]

I wouldn't be able to advise without know which tools you have (or don't), but if memory serves, you're using a fairly dense particle board which can be brutal on blades, so drilling holes is probably going to be your best best. If that's what you go with, you'll need many to adequately supply air for the exhaust port. If say your exhaust is 4" dia, how many 3/8" holes would be needed to equal a 4" hole? You also need to be concerned about the light leaks that inlet port(s) will make and how you're going to counteract that.

 

[FiveToMidnight]

I wouldn't be able to advise without know which tools you have (or don't), but if memory serves, you're using a fairly dense particle board which can be brutal on blades, so drilling holes is probably going to be your best best. If that's what you go with, you'll need many to adequately supply air for the exhaust port. If say your exhaust is 4" dia, how many 3/8" holes would be needed to equal a 4" hole? You also need to be concerned about the light leaks that inlet port(s) will make and how you're going to counteract that.

I have a few tools, nothing too advanced though. I have a hole saw for a drill which I will use to make a 4" hole for the exhaust. I have other sizes too so I can make quite a range of holes lol. Its 18mm MDF Board, so not too hard to cut through.
I will be using PVC elbows in a similar design to something you showed me previously so it should cut out the light.

 

[Skybound]

less airflow is needed for veg and more for flower.

 

[FiveToMidnight]

less airflow is needed for veg and more for flower.

I ended up getting some 90mm 90 degree PVC elbows with some grates to fit on the end. I also have flat black spray paint to paint the inside of them and put them in an S shape. I think that should stop most light but I will have heaps of left over ducting if I need something more

 

[FiveToMidnight]

Well everything has been ordered box wise. I have all the stuff for the ventilation and just waiting on the LED light and the fan control which should arrive next week. I have even ordered seeds!

All I need to get now are the pots, growing medium and nutrients, then I think I should be good to start. Any advice on that sort of stuff?

 

[Skybound]

Grow styles seem to be influenced by shipping restrictions, so it's kind of hard to advise if you're in another country, but if you're in the US, I suggest setting up a "Simple Hydroponics" grow. General Hydroponics nutrients has easy to follow recipe, and there are quite a few documented grows. Simple Hydro is a new(ish) style that is just rockwool, but it's cut into tiny 1cm x 1cm cubes, or 1/4" x 1/4". It's sold per cubic feet and generally 1 cubic foot per large plant. Growing this way gives the grower the forgiveness and stability of a soil grow, but still the rapid growth and heavy yielding of hydro. This is the first style of hydro I tried and found it to be easy to learn, just try to adhere to the core concepts and all will go well. I dabbled in DWC and Aeroponics, but those ended in root rot (pythium) as I was unable to maintain cold res temps. With Simple Hydro, you don't have to maintain a cold res, nor do you need to aerate it. It top feeds the potted plants anywhere from once to four times daily, and I'd bet it can feed more times if grower desired. Use of "beneficial bacteria" in soil and hydro will equate to larger healthier root mass that will further produce higher quality and more weight. In Simple Hydro (often referred to as Capn Style), the key is to extend the veg period to focus on root mass development below and skeletal branching above, but seeing as you're limited to a confined space, you're going to have to do a grow front to back so you need to decide what is most important to you, yield or time till that yield. I'm following a journal where the grower begins bloom immediately after true leaves open on seedlings and yields roughly a half ounce. SOG growers generally veg for 3 weeks and take a QP, Capn style is in veg for 3+ months and frequently harvests more than a pound per plant, but the 2 biggest factors regardless of chosen grow style are time in veg, and the use of beneficial bacteria.

I have no experience with soil yet, but I'm sure the knowledge of hydro can be made to apply in soil.

 

[FiveToMidnight]

Grow styles seem to be influenced by shipping restrictions, so it's kind of hard to advise if you're in another country, but if you're in the US, I suggest setting up a "Simple Hydroponics" grow. General Hydroponics nutrients has easy to follow recipe, and there are quite a few documented grows. Simple Hydro is a new(ish) style that is just rockwool, but it's cut into tiny 1cm x 1cm cubes, or 1/4" x 1/4". It's sold per cubic feet and generally 1 cubic foot per large plant. Growing this way gives the grower the forgiveness and stability of a soil grow, but still the rapid growth and heavy yielding of hydro. This is the first style of hydro I tried and found it to be easy to learn, just try to adhere to the core concepts and all will go well. I dabbled in DWC and Aeroponics, but those ended in root rot (pythium) as I was unable to maintain cold res temps. With Simple Hydro, you don't have to maintain a cold res, nor do you need to aerate it. It top feeds the potted plants anywhere from once to four times daily, and I'd bet it can feed more times if grower desired. Use of "beneficial bacteria" in soil and hydro will equate to larger healthier root mass that will further produce higher quality and more weight. In Simple Hydro (often referred to as Capn Style), the key is to extend the veg period to focus on root mass development below and skeletal branching above, but seeing as you're limited to a confined space, you're going to have to do a grow front to back so you need to decide what is most important to you, yield or time till that yield. I'm following a journal where the grower begins bloom immediately after true leaves open on seedlings and yields roughly a half ounce. SOG growers generally veg for 3 weeks and take a QP, Capn style is in veg for 3+ months and frequently harvests more than a pound per plant, but the 2 biggest factors regardless of chosen grow style are time in veg, and the use of beneficial bacteria.

I have no experience with soil yet, but I'm sure the knowledge of hydro can be made to apply in soil.

I was looking at using Coco Coir as I have seen it mentioned many times as an easy first timer grow medium. Plus I can get it at the local garden/hardware store for pretty cheap.
I will have to order nutrients but that seems to be fairly easy, even here in aus.

I guess time between yields is my main focus right now and was thinking of about 3-5 weeks of veg, mainly because I have seen a few journals using this time period and achieved good yield. 3+ months seems a bit too long for me I think.

I was told able some nutes specificly designed for Coco Coir and some kits you could get with all the nutes you will need for your recipe. I thinking this might be the easiest way to go for the first time

 

[Skybound]

Being is Aussie country, keep an eye out for other successful growers on the web and also down under, and make note of their routines, nutrients they use, are they available for questioning or any other supportive element that would apply. Also, if this will be your first grow, you'll be way more in tuned to every little shift or change so take good notes to monitor responses to techniques you try, and also responses to nutrients. Not knowing a lot about coco, I do know that many growers have been using it for quite a long time which is a statement in and of itself. I expect your grow will go very well and I like the veg time you chose, I think it will jive well with the cabinet height. When you start a journal, please PM me the link as this thread is someone else's.