Questions on ventilating a grow tent.

I haven't even got the tent yet I'm just trying to figure out how all of this works so I don't over or under spend. I'll be using this tent http://cgi.ebay.com/48-x48-x78-Reflective-Mylar-Hydroponics-Grow-Tent-Room-/230629328265?pt=LH_DefaultDomain_0&hash=item35b2944589 with a 400 MH/HPS and 4x 125w CFL (2x 2700k 2x 6500k) going for 6-8 plants. This is my first grow, I've done a lot of research and have what looks like a pretty decent plan drawn up except for the ventilation. Still iffy about how it works. I will be using a carbon filter and my MH/HPS will have a cool tube reflector soo... Ventilation would go? 6" Inline fan (inside tent) > blowing into carbon filter > ducting > light > continue ducting on other side to the exhaust hole and out? That one air current is going to blow its way through the filter and ducting across the light into the ducting on the other side and out of the tent? this doesnt sound right to me. Any help would be appreciated. Also not sure at which parts I'll need a flange, I'm guessing where the ducting connects to the reflector and exhaust port... so a total of 3?

p.s. the only intake I plan on using will be passive via the two vent flaps that I'm guessing will be left open at all times? with two small oscillating fans inside for flow.

6" should be fine. With the carbon filter though, you need to be sucking air, not blowing air into it. So you should have Carbon Filter > ducting to first side of cooltube > ducting on 2nd side of cooltube > fan > ducting to exhaust vent at the top of the tent. If noise is an issue for you then get the fan put inside a box with insulation inside it and seal it inside - the fan will keep cool enough with the airflow going through it and also if possible, keep the fan inside the tent. It will be nice and quiet

Hello: I use that sized tent along with a 400w mh/hps light (dont really see the need for extra cfl's) I have my inline fan (400cfm) mounted to a wall outside my tent. The inline fan sucks air from the carbon filter, into the cool tube light fixture and then exhaust it outside. I have my inline fan running 24/7 for airflow and scent reasons. The light is run on a digital timer. 6-8 plants would be alot for that sized tent, unless you plan on doing a sog or keeping them very small. I find 4 plants is perfect for that sized tent. I harvest about 8-10oz on each grow with pleanty of fine trimmings for making bubble hash or butter. I mounted a dual window fan inside the top of my tent (blows down on plants) and it works great (moves alot of air and stays out of the way) you can find these fans everywhere http://cgi.ebay.com/Westpointe-Dual-Twin-Window-Fan-NIB-/360354593078?pt=LH_DefaultDomain_0&hash=item53e6ceb936 this isnt the excat one I have but pretty much the same thing. Sounds like you have a good plan, good luck and enjoy the growing

Stlmatt

Thank you guys so much that really cleared up my confusion ++rep. And I plan to use auto flower seeds for my first grow and from my understanding they dont get very big? I'd like to get 6 in there if i end up using a 400w MH/HPS (will have 67,000) lumens with CFLS or maybe I could just get a 600w MH/HPS save a few $s and have even more lumens ( way more than minimum for 6 plants)... But then I won't have as many spectrums of light but it will save me a good 250$. Will adding 4x 125w Cfls (2x 6500k and 2x 2700k) be worth it? Probably not so I'll just go with 6 auto flower plants at a time on the 600w. I still have lots of reading to do before I even begin purchasing materials... One thing I'm unclear on is when to start introducing nutes to auto flower strains and if I should even bother trimming or topping/fimming since they grow so fast. I'll be using Canna - Rhizotonic, Terra Vega, Terra Flores, Cannazym and PK 13/14. If anyone has used similar nutes with an auto flower strain I really need to know how and when to introduce each nute. Also I'm slightly iffy on what medium to first plant the seeds in. I'd like to use peat pots to make transplanting easier (assuming theyre not detrimental to root growth?). So in my peat pot just low grade soil 50% perlite and a 1/4 feeding of some mild mild fertilizer or? I think my plan looks pretty solid I'm just unsure of what medium/nutes to directly plant the seeds into to start out with and when to start introducing the other nutes I'm using. I did most of my research before deciding to go with an auto flower strain for my first grow and now I'm lost again >.<

p.s. If I have central air, can I ventilate into my room or even into the central air vent instead of to an open windows? Cold winters here and I'm in an apartment complex with really nowhere else to vent to..

mc260377 said:

6" should be fine. With the carbon filter though, you need to be sucking air, not blowing air into it. So you should have Carbon Filter > ducting to first side of cooltube > ducting on 2nd side of cooltube > fan > ducting to exhaust vent at the top of the tent. If noise is an issue for you then get the fan put inside a box with insulation inside it and seal it inside - the fan will keep cool enough with the airflow going through it and also if possible, keep the fan inside the tent. It will be nice and quiet

Click to expand...

Not trying to kill your ideas but this is a horrible idea. Any leaks between his filter, ducting and light will pull in smelly air since the carbon filter will be causing negative air pressure inside the ventilation setup. The correct setup for this would be

Carbon Filter --> 6" Inline Fan --> ducting from fan to cooltube --> ducting from cooltube out of the tent

And then as far as air coming in you will just use a passive intake. And most fans dont make much mechanical noise if they are hung...just the loud blowing sound...which may lull you to sleep.

eoddom said:

Not trying to kill your ideas but this is a horrible idea. Any leaks between his filter, ducting and light will pull in smelly air since the carbon filter will be causing negative air pressure inside the ventilation setup. The correct setup for this would be

Carbon Filter --> 6" Inline Fan --> ducting from fan to cooltube --> ducting from cooltube out of the tent

And then as far as air coming in you will just use a passive intake. And most fans dont make much mechanical noise if they are hung...just the loud blowing sound...which may lull you to sleep.

Click to expand...

This makes more sense, thank you so much. If anyone could clear up a few of the things from my previous post (same thread scroll up) this would be mucho appreciated!

My setup is going to include

Grow Tent 48'x48"x78" http://cgi.ebay.com/48-x48-x78-Reflective-Mylar-Hydroponics-Grow-Tent-Room-/230629328265?pt=LH_DefaultDomain_0&hash=item35b2944589
600W HPS/MH Conversion Bulb with cooltube 6" reflector http://www.htgsupply.com/Product-Digital-Greenhouse-600-watt-HPS-Grow-Light.asp
Carbon filter 6" Inline Fan Combo http://www.htgsupply.com/Product-GrowBright-6in-Inline-Fan-&-Carbon-Filter-Combo.asp

Besides ducting, circulation fans, nutes, good seed etc this should be more than enough to grow 6 small auto flowering plants correct? Plan on doing only auto flowering for my first few grows just because it seems easier . I'm still iffy about what medium to first introduce seeds to... I'd like to start them off in peat cups preferably with, 50% soil 50% perlite with a mild organic fertilizer or less perlite? A different medium altogether? For nutes I'll be using Canna Rhizotonic, Terra Vega, Terra Flores, Cannazym, Pk 13/14 and I'm not sure on soil yet. Also not sure when to start introducing nutes to auto flower strains as I said before... Also, my room has a central air vent in the ceiling can I just vent into my room or can I/should I go directly to the vent? Don't want to blow all that warm air into there not knowing exactly where it leads. For most small-medium auto flowering strains should I go from peat cups to a 1 gallon pot or 2 gallons maybe?

bump bump bump

You wanna start them easy and get them all to germ go to home depot and pick up one of those little setups with the humidity domes. It comes with the little peatmoss filled disks that you just add water to and throw the seeds in....let sit out of sunlight for 2-3 days and tada...your seeds will be germed. Once you see them start germing you lift one corner of the dome up to let humidity out and once they are all germed you take the dome completely off. After a few days you take the little peat moss thing its planted in and transplant it into another pot.

You want to avoid any ferts when starting from seed for the first few weeks....which means only using nursery soil.

eoddom said:

You wanna start them easy and get them all to germ go to home depot and pick up one of those little setups with the humidity domes. It comes with the little peatmoss filled disks that you just add water to and throw the seeds in....let sit out of sunlight for 2-3 days and tada...your seeds will be germed. Once you see them start germing you lift one corner of the dome up to let humidity out and once they are all germed you take the dome completely off. After a few days you take the little peat moss thing its planted in and transplant it into another pot.

You want to avoid any ferts when starting from seed for the first few weeks....which means only using nursery soil.

Click to expand...

Even with auto flower strains? and I've never heard of germinating like that

@eoddom, thanks for pointing that out about possible leaks - gonna change my setup even though I have never had problems with smells the way I have it at the moment but I defo see where you are coming from

the tent you chose is first class

No problem mc260377.

With any plant you dont want to fert at the very beginning...its going to kill the plant. When i took all of my horticulture plants we also made a nursery soil to start plants in which comprised of just 10 parts sand/5 parts perlite/5 parts peat moss. The only difference between that and the normal soil we made is we threw in slow release fertilizer into the soil mix. We also ferted the plants every other day and did lots of foliar feeding.

eoddom said:

Not trying to kill your ideas but this is a horrible idea. Any leaks between his filter, ducting and light will pull in smelly air since the carbon filter will be causing negative air pressure inside the ventilation setup. The correct setup for this would be

Carbon Filter --> 6" Inline Fan --> ducting from fan to cooltube --> ducting from cooltube out of the tent

And then as far as air coming in you will just use a passive intake. And most fans dont make much mechanical noise if they are hung...just the loud blowing sound...which may lull you to sleep.

Click to expand...

Really? See that has me confused.

My last crop stunk like crazy so I decided to buy a carbon filter and 5" reck extraction fan, the supplier along with the instructions that came with both said for the best results to mount the filter OUTSIDE the tent as follows;

Ruck fan (inside, top of tent) >>>> Ducting>>>>Filter (outside)

The set up works cos it literally killed the smell completely and I get negative pressure in my tent, the other thing with it being installed like this means I can add a piece of ducting to the extraction fan and hook it straight to a cool tube.

So Im "pushing" air through the carbon filter, not "pulling" it through and the whole set up works perfectly, you cant smell anything.

Is this wrong then? should my carbon filter be INSIDE my grow tent?

Cheers in advance for the help