First Grow - Seeking Advice for ventilation - have grow tent & cooltube, now for the rest

[Nic Barlor]

Hi everyone, s'all good?

TL;DR Worried about probable temp. & humidity issues once I start my first grow. Live in a tropical climate

So I'm fixing to start my first ever grow op in either early/mid December or early January. Today I went and got the tent, a Secret Jardin DR90, and my reflector, a 5" cooltube which accommodates a 250W or 400W HID bulb.
The DR90 is ~3'x3'x6' (90x90x185cm) (https://www.hydroculture.co.uk/secret-jardin-dr90).

Since this is my first grow, my goal is to get at least 6 oz out of 3 plants (1 mo. veg/6-8wk flower) using GH Flora series nutes (how realistic is that for a goal?). I would grow 4 or 5, but all the seeds I have are in sets of 3 per strain, and I don't want the trouble of dealing with different flowering periods.

Since I live right on top of the Tropic of Capricorn (basically only have 2 seasons), it gets really hot and humid summers (spring is pretty hot and humid, too) and mild & dry winters (48-68 Fahrenheit, sometimes low 70s) .

That said, I'm kind of worried about my worst summer enemies (which are approaching - currently spring), so I am thinking about running a 250W MH for veg and either 250W or 400W for flower.
I still don't know what kind of temps I am going to manage in the tent, so I'm here to minimize any mistakes.
I wanted to run a 5" inline exhaust for shoving air out, and 1 or 2 4-5" extractor fans for the intake at the bottom.

I don't have a mobile air conditioner or dehumidifier.


If anyone lives in similar conditions (or even if not), any input is much appreciated. Thanks in advance!

 

[hippee]

Hi Nic ,sounds like you are gonna have your hands full,I too am growing for the 1st time in a tent but my conditions are much better,I think you are on the right track with the fans,is there a way you could take the air for your inlet from under the house it might be a bit cooler also I've been reading the grow bible, its very important to get the right exchange of air,so much in so much out in a given time if you have it at optimum it will help a bunch,I have dealt with this in my other grow space and it truly works I can't remember the formula but if somebody else doesn't post it I will when I get home Sun. good luck to you as for your quantity it's attainable but you gotta be dialed in especially with those conditions

 

[Nic Barlor]

Hi Nic ,sounds like you are gonna have your hands full,I too am growing for the 1st time in a tent but my conditions are much better,I think you are on the right track with the fans,is there a way you could take the air for your inlet from under the house it might be a bit cooler also I've been reading the grow bible, its very important to get the right exchange of air,so much in so much out in a given time if you have it at optimum it will help a bunch,I have dealt with this in my other grow space and it truly works I can't remember the formula but if somebody else doesn't post it I will when I get home Sun. good luck to you as for your quantity it's attainable but you gotta be dialed in especially with those conditions

Hi there, hippee, thanks for the input.

Yeah, these climactic conditions are really gonna test my dedication and adaptability.
No, there's no way for me to draw air in from underneath my place because I live up on the 3rd floor of an apt building.

By "the grow bible", do you mean Jorge Cervantes' book?
Yes, I've heard several different figures regarding air exchange and I've decided that 3 or 4x the grow tent volume in air flow should suffice (and the inline exhaust I'm looking at satisfies those numbers).

I went ahead and drew a partial floor-plan of my apt so y'all can get an idea of my ventilation situation.
The spare room where the tent will go only has one window, more or less at eye level (~5'7"), out of which I am going to shove my air.
My intake is going to be a little complicated though... The laundry room has a big window (adjacent to my neighbor's laundry room window) that constantly refreshes any air in the vicinity (so long as the door to that side of the house is open/ajar, allowing for air flow).

I could either pull air directly from outside, or from the inside of the house/laundry room.
You'll see there is a dogshit minefield. This is only relevant because I'm not sure if any bacteria that my dog harbors in its intestines, or any that cling to her shit once she has done her business, could contaminate the air I am pulling into my tent (if I were to just pull air from just outside the tent/the inside environment, as opposed to pulling air directly from outside).
I mean, I pick up her shit regularly, but since I'm not always home, my dog has learned to shit near where we keep the washer and dryer, on top of a doggy doo mat.

If I do have to pull air in directly from the outside, I'm gonna have a big kink in my ducting (>90 degrees, basically a U-turn), which I know restricts air flow because a) physics and fluid dynamics, and b) Jorge Cervantes says so in all his books.
I just don't know if this hypothetical air flow restriction would be that big of a problem since it's for pulling air in, and not pushing it out.


Thanks for reading up to here!

 

[fandango]

i use a 6" inline blower(plenty of sound comes from it/maybe build a sound box to put it into)
25' of flex duct and a carbon filter.
1. intake from window..make a bend in the tube so the light stays out...run this into the tent
2. suck air out from the tent through the carbon filter/fan/exit air at window
3. leave tent open lights on

 

[Roger A. Shrubber]

and where'd you get 5 inch? thats a weird size, all the fittings you're going to find at the hardware go in even 2 inch increments, 2,4,6, 8 inch. unless you have a way better stocked hardware than i have, you're going to have to end up ordering stuff and waiting for it to arrive.
and i know you're excited about getting started, and i won't say wait this time, but in the future, consider growing in the winter and taking the summer off. i shut down in june, july, august, and september. why fight the heat and get huge electric bills? just grow your ass off the other 8 months a year

 

[Nic Barlor]

and where'd you get 5 inch? thats a weird size, all the fittings you're going to find at the hardware go in even 2 inch increments, 2,4,6, 8 inch. unless you have a way better stocked hardware than i have, you're going to have to end up ordering stuff and waiting for it to arrive.
and i know you're excited about getting started, and i won't say wait this time, but in the future, consider growing in the winter and taking the summer off. i shut down in june, july, august, and september. why fight the heat and get huge electric bills? just grow your ass off the other 8 months a year

Hey Roger, 5" is actually just an approximation. I deal with the metric system, so it's actually 125mm inline exhaust (so 4.921"), and I'm thinking about 100/120/125mm intake fans.

I highly doubt where I live I have better stocked hardware stores than you. DIY culture isn't strong where I live. People are idiots and buy most shit premade because they are too wimpy & 'tarded to do things themselves. End result: everything is expensive, finding tiny specific parts for very specific projects is difficult as fuck (TMW you hit up every major hardware store in town and STILL can't find a specific part/piece, makes me mad as hell). Most awesome DIYs projects (grow-related or otherwise) I see on YouTube, Instructables etc, are just out of reach for me because you need that one piece that "can be found at any hardware store" - except where I live.

As for not growing in the summer... Yeah, perhaps a good idea next time. I mean, on the one hand I'd like to grow in the summer just to see if I can (gonna run temperature tests before actually starting), but on the other hand, the heat and humidity is real.
I have dozens of bagseeds (many are probably viable) and only 15 good genetics seeds. Should I maybe try growing bagseed now in the summer? It might be more acclimated to this bullshit climate anyway... From what I hear from other people in town, the bagseed here is mostly sativa/sativa-dominant. The same people, however, tell me that it's not worth investing all this money in a sophisticated grow op just to try and grow some bagseed.. Which it obviously isn't, but just as a trial run, so as to not kill one of my good girls with this weather. Idk. The electric and water bill alone should be enough to deter me from growing bagseed.

Alas, I only wish that the other 8 months of the year were comfortable enough to not have to worry. The reality is that it is usually hot from mid-September/early-October to early/mid-February, then so-so between mid-Feb and late-May/early-June, then it gets kind of cold (never really gets under 48F at most), and stays cold up until late August (if I'm lucky, I get 2, maybe 2.5 cold months out of the year). I've literally had "winters" where it was only cold for 2 or 3 weeks before surging back up to the 70s/low 80s.
This year we had an exceptionally long and cozy (i.e., cold) winter, where it was cold from early June all the way to early September.

Thanks for the input, m8. =D

i use a 6" inline blower(plenty of sound comes from it/maybe build a sound box to put it into)
25' of flex duct and a carbon filter.
1. intake from window..make a bend in the tube so the light stays out...run this into the tent
2. suck air out from the tent through the carbon filter/fan/exit air at window
3. leave tent open lights on

Hiya fandango!

Wait, so are you saying I should keep my tent open while the lights are on to minimize heat problems?
I'll look into building a sound box for the exhaust if I find it to be noticeably loud (will probably run a sound test at night, too, to see if any neighbors could hear a buzzing from the hall).

Ah yes, the bend in the intake duct will keep out light.
Thanks for your input!

 

[Roger A. Shrubber]

yes, leaving your tent open during lights on makes it easier to keep it cool most of the time, just more air flow.
i put my exhaust fan in a big plastic tote and packed old clothes and foam rubber pieces around it to keep it quiet

 

[Nic Barlor]

yes, leaving your tent open during lights on makes it easier to keep it cool most of the time, just more air flow.
i put my exhaust fan in a big plastic tote and packed old clothes and foam rubber pieces around it to keep it quiet

I see. Makes perfect sense, but what about mold, pests, and humidity control? I'm going to clean the room where the tent will go very thoroughly, but it's not a sterile environment..
Wouldn't I expose myself to bigger issues by leaving the tent open in the middle of a humid summer?

 

[Roger A. Shrubber]

no

 

[Roger A. Shrubber]

its a tent, not a fortress or a sterile environment. zipping the tent up won't stop mold, pm, mites, thrips, or even fungus gnats

 

[fandango]

Hey Roger, 5" is actually just an approximation. I deal with the metric system, so it's actually 125mm inline exhaust (so 4.921"), and I'm thinking about 100/120/125mm intake fans.

I highly doubt where I live I have better stocked hardware stores than you. DIY culture isn't strong where I live. People are idiots and buy most shit premade because they are too wimpy & 'tarded to do things themselves. End result: everything is expensive, finding tiny specific parts for very specific projects is difficult as fuck (TMW you hit up every major hardware store in town and STILL can't find a specific part/piece, makes me mad as hell). Most awesome DIYs projects (grow-related or otherwise) I see on YouTube, Instructables etc, are just out of reach for me because you need that one piece that "can be found at any hardware store" - except where I live.

As for not growing in the summer... Yeah, perhaps a good idea next time. I mean, on the one hand I'd like to grow in the summer just to see if I can (gonna run temperature tests before actually starting), but on the other hand, the heat and humidity is real.
I have dozens of bagseeds (many are probably viable) and only 15 good genetics seeds. Should I maybe try growing bagseed now in the summer? It might be more acclimated to this bullshit climate anyway... From what I hear from other people in town, the bagseed here is mostly sativa/sativa-dominant. The same people, however, tell me that it's not worth investing all this money in a sophisticated grow op just to try and grow some bagseed.. Which it obviously isn't, but just as a trial run, so as to not kill one of my good girls with this weather. Idk. The electric and water bill alone should be enough to deter me from growing bagseed.

Alas, I only wish that the other 8 months of the year were comfortable enough to not have to worry. The reality is that it is usually hot from mid-September/early-October to early/mid-February, then so-so between mid-Feb and late-May/early-June, then it gets kind of cold (never really gets under 48F at most), and stays cold up until late August (if I'm lucky, I get 2, maybe 2.5 cold months out of the year). I've literally had "winters" where it was only cold for 2 or 3 weeks before surging back up to the 70s/low 80s.
This year we had an exceptionally long and cozy (i.e., cold) winter, where it was cold from early June all the way to early September.

Thanks for the input, m8. =D



Hiya fandango!

Wait, so are you saying I should keep my tent open while the lights are on to minimize heat problems?
I'll look into building a sound box for the exhaust if I find it to be noticeably loud (will probably run a sound test at night, too, to see if any neighbors could hear a buzzing from the hall).

Ah yes, the bend in the intake duct will keep out light.
Thanks for your input!

If the outside air is favorable,than you can blow the clean air from the carbon filter back into the room.And the inline blowers make a ton of noise ...just need to box it with sound padding

 

[RDT]

i use a 6" inline blower(plenty of sound comes from it/maybe build a sound box to put it into)
25' of flex duct and a carbon filter.
1. intake from window..make a bend in the tube so the light stays out...run this into the tent
2. suck air out from the tent through the carbon filter/fan/exit air at window
3. leave tent open lights on

Would there be any possible way to get a picture of yours

 

[fandango]

My current set up is not complete right now.What I did was just buy the inline fan/carbon filter and the 25' tube and plugged it into the wall outlet in my grow area.Before I was having problems with the drying flowers smelling up the air in front of the house.Visitors would be walking up to my front door and mention the weed smells coming at them from the side walk.
What happens with the filter and blower running is the whole house air is drawn into the filter and the air that the blower expells is clean.

 

[Roger A. Shrubber]

know you weren't asking me, but i thought you might like to see an actual working set up. in through the filter, through the light
into the fan, in this tote full of foam rubber and old clothes to muffle noise
in hot weather it goes out the wall vent thats capped here, since its cold outside, i have it venting by this big blower thats blowing the heat out of my flower area into the rest of the house. why pump hot air outside then pay more to make hot air in another room?

 

[RDT]

know you weren't asking me, but i thought you might like to see an actual working set up. in through the filter, through the lightView attachment 3831340
into the fan, in this tote full of foam rubber and old clothes to muffle noise View attachment 3831341
in hot weather it goes out the wall vent thats capped here, since its cold outside, i have it venting by this big blower thats blowing the heat out of my flower area into the rest of the house. why pump hot air outside then pay more to make hot air in another room? View attachment 3831342

Thanks

 

[Nic Barlor]

know you weren't asking me, but i thought you might like to see an actual working set up. in through the filter, through the lightView attachment 3831340
into the fan, in this tote full of foam rubber and old clothes to muffle noise View attachment 3831341
in hot weather it goes out the wall vent thats capped here, since its cold outside, i have it venting by this big blower thats blowing the heat out of my flower area into the rest of the house. why pump hot air outside then pay more to make hot air in another room? View attachment 3831342

Thanks a bunch, Roger! That really helps.
Also, good thinking rerouting the hot air back in the house during the cold months,
I'll probably do something similar.

Do all those bends in the ducting not severely reduce your airflow out, or can the exhaust handle that just fine? Do the bends help reduce the whooshing of the air?
Also, in your particular setup, assuming things weren't as quiet as they are, at which point would you use a piece of insulated ducting?

 

[Roger A. Shrubber]

if it was a lot longer the bends would hurt, the whole thing is less than 20 feet of hose from the filter to the outlet.
insulated ducting? like a silencer? right before the exit, i would assume, never used one.

 

[Nic Barlor]

So just to give y'all an update:

I now have the following materials:
- 1 cooltube reflector
-1 250W mag ballast
-1 250W MH bulb
- 3 small (~1L, 1.5L?) plastic pots
- 3x 15L smart pots
- 1 125mm (5") exhaust fan
- 1 150mm intractor fan
- 2x 20cm oscillating fans
- 1 90x90x185cm Secret Jardin DR90
- 1 pH meter
-1 TDS meter
-1 set pruning scissors
- 50L 50-50 Promix
- 5m ducting
- 1 light hanger
- 1 43W CFL (or 36W? not sure)
- GH Flora Trio
- Jump-start seedling/clone chamber

Come flowering time, I'm going to get a 400W mag ballast and 400W HPS.

Aside from that, would y'all say that I am ready to pop a bean?
Obviously I still have to set up my tent, mount my ballast on the wall and just put everything together, but am I missing anything?

Apparently, you need pH Down & Up no matter what kind of water you're using? I'll be using tap water which has been left out to evaporate Chlorine.

Would I also need CalMag if I'm using tap water?

 

[coreywebster]

I'm not sure what an intractor fan is but I assume its an extractor used for intake. If both fans are the same type (inline) then you want the biggest fan as extractor and smaller fan as intake. Your extractor fan will lose 15-20% power with a filter and ducting so it has to be stronger than your intake to assure negative pressure in the tent. If you have the opposite then positive pressure will push uncleaned air out and you will have a smell in the whole house. Keep negative pressure or at least never have positive pressure and the smell will be controlled.
You may find you need a dehumidifier to keep humidity down in your climate.
I have never grown in your climate and although it may present more problems for you there are not many that cant be overcome.
Good luck! Happy growing

 

[Nic Barlor]

I'm not sure what an intractor fan is but I assume its an extractor used for intake. If both fans are the same type (inline) then you want the biggest fan as extractor and smaller fan as intake. Your extractor fan will lose 15-20% power with a filter and ducting so it has to be stronger than your intake to assure negative pressure in the tent. If you have the opposite then positive pressure will push uncleaned air out and you will have a smell in the whole house. Keep negative pressure or at least never have positive pressure and the smell will be controlled.
You may find you need a dehumidifier to keep humidity down in your climate.
I have never grown in your climate and although it may present more problems for you there are not many that cant be overcome.
Good luck! Happy growing

Hello Corey,

By intractor fan (which now that spellcheck is on, I realize is not a word) I mean a simple fan like this:

The exhaust fan is the more powerful of the two, despite its 125mm diameter vs 150mm diameter; it moves ~230 cubic meters/h on low and 280 cubic meter/h on high.
The 150mm fan moves like 275 cubic meters/h, according to the hydro shop's website, but now I'm confused...
My 125mm exhaust fan is like this (the black and green one):

For one, I paid like 2x what I did on simple fan for exhaust fan. Secondly, the black&green fan is the one you're used to seeing extracting air from the grow tent.. Thirdly, the shop clerk/manager sold me both of these, suggesting I use the white one for pulling air in (due to bend in ducting for air intake) b/c the 125mm simple fan was too weak, then use the black&green to suck out. It all made sense, but I don't see how a supposedly 30W 150mm fan could move more than this monster I bought specifically for pulling out air..

I'm aware of the fact that I need negative pressure, but now I'm confused by the specs on hydro shop site...


At this moment, 12:22 pm, Google says it's 90F/32C and 43% RH here atm. Can confirm, my body feels like it's melting in a very dry way. After it rains, RH will probably go to like 70s/80s. Been dry these past few days..