to vent or not to vent

R

rnwy29erclr

New Member
hello, my grow room is 8x15x8 8 wide - 15 length - 8 high
have 1 -1000k hps do i need to vent the grow room? my lights on temp are 76
my lights off are 68, i have a humity meter and it reads 70 am in flower day 26
 
rnwy29erclr said:
hello, my grow room is 8x15x8 8 wide - 15 length - 8 high
have 1 -1000k hps do i need to vent the grow room? my lights on temp are 76
my lights off are 68, i have a humity meter and it reads 70 am in flower day 26
Click to expand...

Sounds like a nice size room. How many plants do you have in there? 70% RH is a bit high, are you venting the room at all bro? pics?:popcorn:;)
 
i'm not trying to argue i just thought i herd someone on this forum say that if your grow room is big enuff, just by opening the door a couple times a day would be enuff venting, any else remember?
rnwy
 
Your plants can use 5x the natural amount of co2 avail. it gets what it can from LOTS of clean fresh air so unless your gonna run co2 and dehumidifiers, you MUST vent and keep the air moving around your plants. Otherwise your plants will suffer and mold!!! My room is not big but I take 80 pints of water a day out of my 2 dehumidifiers (over 5gls) to keep it at 50 to 55% RH. At 70% you will get rot and ruin all your hard work!!! Now go fix it and good luck:popcorn: and post up your changes so we can see it !
 
Hiya - sounds like you're on track. Good job asking the question. And the real answer is not should you vent, but how much.

There are two main reasons to vent:

1 - to control the temp/humidity - you can get the ideal numbers from many sources but I think the basics are veg and grow areas should ideally be as close to 50% as possible and 78F. The farther you get away from 50 upwards, depending on your temp and lighting you risk mould and all kinds of other problems. If you go too low, you will be forcing the plants to transpire more than you should. Some people say low humidity in Veg helps promote females, but it also slows their initial growth - when the roots and stems have not developed enough to bring water up when the humidity is low. Same reason you cut the leaves on clones and put them in a dome, but you DO NOT want the dome on seedlings because they will get mouldy.

2 - to provide the plants with fresh air. This is kind of a funny thing. When we say fresh air - we think lots of oxygen. When the plants think fresh air - they want lots of CO2. In nature there is about 350-400ppm CO2. If there is no circulation, your plants can go through that much CO2 in about 15 minutes. Your plants can handle up to 1500-2000ppm for increased growth. So basically when you vent air in - you're bringing in that CO2 they need. If you have a CO2 generator or tank then you want to keep that CO2 in - so you only vent when you have to - to control the temp or humidity.

Hope that helps - GL and keep up the good work!
 
fastfor20 said:
Your plants can use 5x the natural amount of co2 avail. it gets what it can from LOTS of clean fresh air so unless your gonna run co2 and dehumidifiers, you MUST vent and keep the air moving around your plants. Otherwise your plants will suffer and mold!!! My room is not big but I take 80 pints of water a day out of my 2 dehumidifiers (over 5gls) to keep it at 50 to 55% RH. At 70% you will get rot and ruin all your hard work!!! Now go fix it and good luck:popcorn: and post up your changes so we can see it !
Click to expand...

hey fast i'm lookin to get a dehumidifier but in the meantime i'm leaveing the door open to my grow for now my grow room is in side a very large building,
i did notice that the humidty was high on days that it rained now my humidity
is reading avg 59 but dose drop down to 49-48 sometimes
 
rnwy29erclr said:
hey fast i'm lookin to get a dehumidifier but in the meantime i'm leaveing the door open to my grow for now my grow room is in side a very large building,
i did notice that the humidty was high on days that it rained now my humidity
is reading avg 59 but dose drop down to 49-48 sometimes
Click to expand...
Your in flower you cant take a wait and see view to much is on the line. Keep the fans going you need lots of air moving all the time. It would blow to lose it all to mold. If you dont have any heat issues maby a space heater to help dry it out a bit? 59% is still to high at your stage:cheer: good luck bro keep at it :))
 
Hi - the other option is just a wall fan. Sufficient air across the leaves at 58% humidity and you should be safe. Basically if you've got leaves overlapping and sitting on each other - that's bad. If you've got airflow of any kind in between you're much safer. Mold is a big gotcha. One of the few ways you could really lose your whole crop right at the end.
 
Whiskey Papa said:
Hi - the other option is just a wall fan. Sufficient air across the leaves at 58% humidity and you should be safe. Basically if you've got leaves overlapping and sitting on each other - that's bad. If you've got airflow of any kind in between you're much safer. Mold is a big gotcha. One of the few ways you could really lose your whole crop right at the end.
Click to expand...

ok if i buy a dehumidifier do i need to buy the $250.00 - $300.00 whats the trick
can i make one?
thanks. rnwy
 
I found it very hard to figure out which dehumidifier to buy. I think fastfor20's tip of looking at the reviews is a good start. I can tell you that even for 5 decent plants - I got a 25 pints a day and it didn't make a difference. Then when I went to 70 it works fine - but there is some heat generated (and some noise.) I would definitely err on the side of caution and get one larger than you think you need if you can squeeze it in - both physically and financially. But remember you will have to account for the heat.

GL - seems this one is a very hard piece of gear to get right the first time for many of us.
 
i'm trying to think how to vent my flower room without letting light in
i do have a very very large exhaust fan now in flower room but no return air any suggestions?
thanks , rnwy
 
That's a tricky one. No easy answer other than to do as was suggested and baffle it. You can buy them or build them. The good thing is with the incoming vent - unlike the fan ducting - extra turns and bends isn't bad - in fact its necessary to baffle it. See if that gives you any extra help (ie. using a length of ducting to someplace dark or baffling the end of the ducting).
 

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