12/12 Ventilation Question

OK. Here it is. I'm planning to switch my plants to 12/12 in a bit. Im be flowering in a tent. My room is not completely dark and I'll have to close passive intake flaps during dark time. My question is concerning fresh air during dark time. Will my girls need constant fresh air intake during this time. And if 100% so how do I get them fresh air without letting in light and stressing them. ( I will have a dehumidifier inside tent if that's relavent or not.) So, do my girls need constant fresh air during dark cycle and how to maintain this with passive intake holes closed? Has anyone kept holes closed without letting in fresh air and had a successful crop? Any help or advice is highly appreciated. So far (3 grows) I've only grown auto so they've always run 24/0 without concern for dark time. So far on this grow I've been vegging 24/0 as well. Thanks.

I have never tried what you are attempting but I would would allow fresh air in the tent at all times. If your tent is not light tight when you have the vents open you can build a light trap out of cardboard and duct tape, or I am sure there is some solution for this problem at the local hydro store for way to much money lol.

Thanks Num for the quick response. But here it is my tent is light proof. However the room its in will not be. So during dark period if I have passive flaps open light will surely come in through the intake. Q. When you do your dark cycle do yo leave passive intake holes open? Or how do you allow your tent to receive fresh air if they're closed?
That's a pretty good idea to build some type of trap with ducting b/c you are right the hydro store will have a solution but it'll probably cost me a finger or two. Lol.
I'm thinking about buy some small booster fans with ducting for intake and exhaust. Maybe that'll work. I'm just so pressed for money right now. Lol.
Hey check out my current grow if you have time. Its called "First time for everything" on this forum. Let me know what you think. I'm about to post current pics in about 10 minutes or so. Thanks.

You can buy cheap booster fans at home depot if you choose to go that route. How big is your tent, and how are you cooling your light? The light traps are going to be your cheapest way man. Here is how I would set it up if I was you. I would hang a carbon air filter from the sealing if you are using one anyway then run ducting from the filter to my light and then out of the tent. this will cause the tent to have negative pressure forcing it to draw in air from any open vent. Then just make a light trap for the open vent. No money needs to be spent that way unless you need to buy duct tape.

To build a light trap you need to make a box that has 3 sides and a top with no bottom. The 4th wall of the box will be the tent wall. The box will need to be long enough for you to tape at least 3 baffles in it. the baffles are just pieces of card board that are 2/3 the width of the box. Tape one to one side of the box and the next to the other. What this does is force the light to take 90 degree turns which light sucks at. So when it is sitting in front of you it should look like a box missing a side with pieces of cardboard taped to the inside alternating sides. Not sure this will help it is hard to explain without being in front of you. I will make one when I get up today and post a pic so you can see for your self.

Thanks Num. I definitely appreciate the info. Seems like I've been improvising this whole grow. Don't have tons of money to spend. BTW if you can post those pics for me that would be wonderful. Thanks a bunch.

That's growing man seems like every time you turn around you are fighting some new fight. Whats worse is that most of those fights require money to win. But the there is a lot of really cheap DIY fixes out there for a ton of problems that work really well. I was just on a thread called ghetto growing and we were talking about all the bad as shit you can do with a little homework and a few bucks spent at the home depot. Hell I built one of my set ups lights and all out of shit from home depot and that enclosure grows some mean ass bud.

I know. Every day different struggle. Story of my life. Lol. But I've handled it so far. Man I wish I had the skill and tenacity to build my own box. Props to you for that. Maybe somewhere down the line. But for now still bobbing and weaving. Lol.

When you are ready to build a box hit me up ill help you out, I have built everything from little tiny micro boxes to full rooms. Way easier than you think to build a box and can be done so much cheaper in most cases. I would say start out by building micro box it can be done sooooo cheap I built mine out of scrap I had from a different project but the same box could be built for under $50. That includes everything lights, exhaust, reflective material, wood, tape, fucking everything lol. Plus micro grows are the funnest thing in the world its like growing little bonsai trees that get you high.

What Nummingtons is suggesting sounds like a good idea. I have a similar setup but instead of a box I just have long ducting from my passive intake. So some light gets in at the very end, but by the time the ducting gets in the tent there's no light. No light leaks and my ladies have been flowering well.

Kimolos idea will work too I have used ducting before for the same purpose and it should work in your situation unless you have an HID light near the tent in which case light will come right through the foil ducting, but can be fixed by applying foil tape to the ducting. I suggested the light traps cause you said that you were a bit short on cash, plus with light traps you don't end up with ducting laying everywhere lol. So go for it man if you have any extra ducting laying around this will be an easy fix and I wont have to build a light trap today lol.

Nummingtons said:

When you are ready to build a box hit me up ill help you out, I have built everything from little tiny micro boxes to full rooms. Way easier than you think to build a box and can be done so much cheaper in most cases. I would say start out by building micro box it can be done sooooo cheap I built mine out of scrap I had from a different project but the same box could be built for under $50. That includes everything lights, exhaust, reflective material, wood, tape, fucking everything lol. Plus micro grows are the funnest thing in the world its like growing little bonsai trees that get you high.

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I'll definitely do that . I appreciate it.