Beginner here! Grow room test run advice

Hey all,

I’m planning my first grow after some serious research. I took into consideration the advice of many experienced growers and have what appears to be a basic, but decent grow tent setup. I was just wondering if anyone would be willing to give me some advice on a few things:

First, I’m in the process of germinating my seeds and am doing so using the paper towel/Damp cotton method. I’m in the New England area and it has been averaging 60-70 degrees during the day and roughly 40-45 at night. Given we have just entered May, I am anticipating the temperature and humidity will change pretty significantly in the coming weeks. That being said, I have been trying to get a feel for climate control in my grow room. Over the past day or two, I ran my grow light and fans as I would if the plants had sprouted to get a feel for the temp/humidity.

My humidity was averaging very low, 39-42% while the temperature was mid to high 70s without the exhaust fan, and about 70-73 with the exhaust fan on. I read that when your exhaust fan is on (I have the fan connected to a carbon air scrubber as well) it should create a gentle pull/vacuum within the tent and mine is doing that so I think I set it up correctly? I guess my questions are these:

  1. Should I introduce a small humidifier to my grow tent/the room my grow tent is pulling air from? Will this help at all to stabilize the humidity? I will be monitoring the temp and humidity very closely anyway and I was thinking of seeing if I could put a timer on the humidifier and have it come on a few times a day or something to just boost the humidity a bit. I am aware that too much humidity and I could be stuck with mold or root rot.

  2. I am wondering if, given I will be growing in the summer and it will likely get very warm, I should switch my light cycle to come on at night time and have the light cycle finish up in the daytime. I’m considering this and want to know if it’s a good idea because the room I am growing in has an air conditioner that will likely be on at nighttime. I was thinking it might balance out the temperature well given the light gives off heat, but I wanted some opinions on it as I am a beginner!

Oh also, I am growing 2 white widow plants and I know they are high quality seeds because I got them from this site!

Any thoughts/opinions/advice would be appreciated. I can also attach some pictures of my setup if that helps. Thanks I’m advance and I’m sure I’ll be posting again with more questions.


I live in texas and it het hot. So i run my lights 7pm to 1pm for veg the 7pm to 7am for flower. Does your humidity tend to stay the same? If its staying that low all the time a humidifier would be good. The only way it worked for me was to get one that humidifies the entire room my tent is in. I tried sm ones but no. Also i started considering my seasons here. Right now weve got high humidity & im in veg. End of august & sept when i hope humidity goes down i flip to flower. If necessary i have a dehumidifier but it puts out a lot of heat.


Welcome to the forum!! Thats awesome that you are running your tent before hand. I wish everyone did that and 90% of their enviorment problens wouldn’t happen!! I think growing at night is great as long as it fits your schedule. But with you tent right next to the window I would sit in my tent for about 5 minutes with LIGHTS OFF, and look for light leaks you may need to fix once your eyes adjust. What light are you running?

For germination I soak my seeds in tap water for 24hrs then transfer them to a damp paper towel until the tail/tap root is about 1/4 to 1/2 inch long then transplant into whatever you are planning.

Good luck man!!! Happy growing🤙
Keep asking questions if you need!


Welcome to the forum! I’m assuming that’s duct is pulling in fresh air? I’m like @Laurap the small humidifiers don’t do justice. You might be better off like she said and get the room the tent is in under control first. You will probably need a dehumidifier once it gets into flower (maybe)?

Higher humidity in veg is good but not in flower…sorry if you already knew that. I have my intake of the tent hooked up to the exhaust of my dehumidifier to keep my humidity down. It’s not pretty but it works.

I’m in flower and yeah my temp gets up to 80ish, but humidity stays around 30ish and for flower that’s the best I can do. It’s either high humidity and cooler temps, or low humidity and higher temps… so what do you do…lol :joy::joy:
Feel free to tag if you need anything. :sunglasses:

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Hey @Laurap ! Thanks so much for your reply and advice. Yeah, it’s weird, I had my equipment off today and the humidity in the tent now that no air is cycling and no lights are on is up around 62. However, when I turn it on I struggle to keep it in the 40s. I pulled out my humidifier have it near the intake of my tent and I’m gonna test to see if that’s helpful—I feel like it will be.

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Hey @imSICKkid ! Thanks so much for your reply and advice. I’m definitely going to sit in the tent and patch up any light leaks, I have some tape that came with my tent for that purpose. I’m not home at the moment to read the exact make and model of the light. I actually got it a while back, but I remember it was one of the recommended brands from the grow/light guide on the ILGM site.

The germination is actually going well too! They have sprouted small roots as of today! Very exciting stuff.

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Hey @HappyHydroGrower ! Thank you for your reply and advice as well. So I have my exhaust fan hooked up to my carbon air scrubber and the air is pulling from another duct at the bottom of the tent (not pictured). The air from the tent is sent outside—I read some advice that suggested you should not have your exhaust fan blowing the tent air back into the room the tent is in. Should I have it set up differently do you think?

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I wouldn’t have a carbon filter hooked up yet while vegging. I was told the higher humidty will do a number on the filter. Plus, your plants wont stink until they start budding.


@imSICKkid ah, yeah I should have figured as much. Well alright then! I’ll remove it until I need it.

No I just wasn’t sure if it was pulling in or out. That’ll work. Carbon filter is optional. Humidity will ruin a carbon filter. Mine last 1.5 grows. I don’t use it now. Smells not an issues I have to be concerned about right now. Keep in mind that different strains might smell more than others at different stages. My WW on my first grow smelled the worst during late veg through the end of flower. My two sour Diesels smelled up till about two weeks ago but not so much now. I’ll chop one of them Sat.

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@HappyHydroGrower gotcha, gotcha. Yeah to be honest The air filter was part of the tent when I bought it and I figured might as well, but thank you for that information, I suspect I’ll be doing the same after my first grow and ditching the filter!

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Also, keep in mind that venting outside will stink up the neighborhood. Some smell might even make it through the filter. So, if someone can smell it, that might not be such a good idea… just sayin! :wink: :sunglasses:

@Greencoat5 thanks man, I appreciate the info!

So this is totally of topic but I started a grow and now I’m in my second week of flower and my plant is right under lights… I wanted to know if I could reverse my carbon filter PUT IT ON THE OUTSIDE OF MY TENT WITH THE FAN SO I COULD RAISE MY LIGHTS AND GIVE THE PLANT MORE ROOM TO GROW… will that effect my carbon in any manner


You can do this.

I run my exhaust fan and filter on the outside of my tent as well for extra height. Shouldnt be an issue at all

What is the best temperature range to keep your tent